Android radio button not accepting input : I have two classes:

**QuestionModel.java**
  
       package com.invertemotech.quizapp;



     public class QuestionModel {

    public QuestionModel(String questionString, String answer ,String optA, 
     String optB, String optC , String optD) {
        QuestionString = questionString;
        Answer = answer;
        OptA = optA;
        OptB = optB;
        OptC = optC;
        OptD= optD;

    }

    public String getQuestionString() {

            return QuestionString;
    }

    public void setQuestionString (String questionString) {
            QuestionString = questionString;
    }

    public void setOptA(String optA) {
        OptA = optA;
    }

    public String getOptA() {

        return OptA;
    }


    public void setOptB(String optB) {
        OptB = optB;
    }

    public String getOptB() {
        return OptB;
    }

    public String getOptC() {
        return OptC;
    }

    public void setOptC(String optC) {
        OptC = optC;
    }

    public String getOptD() {
        return OptD;
    }

    public void setOptD(String optD) {
        OptD = optD;
    }


    public String getAnswer() {
        return Answer;
    }

    public void setAnswer(String answer)
    {
        Answer = answer;
    }

    private String QuestionString;
    private String OptA;
    private String OptB;
    private String OptC;
    private String OptD;
    private String Answer;


    }


**MainActivity.java**

       package com.invertemotech.quizapp;

     import android.support.v7.app.AppCompat Activity;
     import android.os.Bundle;
     import android.util.Log;
     import android.view.KeyEvent;
      import android.view.View;
      import android.widget.Button;
      import android.widget.EditText;
      import android.widget.ProgressBar;
      import android.widget.RadioButton;
      import android.widget.RadioGroup;
      import android.widget.TextView;
      import android.widget.Toast;

      import java.util.ArrayList;
       import java.util.Collections;
       import java.util.Random;

      import cn.pedant.SweetAlert.SweetAlertDialog;

       public class MainActivity extends AppCompatActivity {

       ArrayList<QuestionModel> questionModelArraylist;

        TextView questionLabel, questionCountLabel, scoreLabel ;
       //    EditText answerEdt;
       //    TextView txtQuestion;
       RadioButton option1, option2 , option3 ;
       Button submitButton;
       ProgressBar progressBar;
       QuestionModel currentQuestion;

       int currentPosition = 0;
       int numberOfCorrectAnswer = 0;


       @Override
       protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        questionCountLabel = findViewById(R.id.noQuestion);
        questionLabel = findViewById(R.id.question);
        scoreLabel = findViewById(R.id.score);
        option1 = findViewById(R.id.option1);
        option2 = findViewById(R.id.option2);
        option3 = findViewById(R.id.option3);
       //        option4 = findViewById(R.id.option4);
        submitButton = findViewById(R.id.submit);
        progressBar = findViewById(R.id.progress);

        questionModelArraylist = new ArrayList<>();
        questionModelArraylist.add(new QuestionModel("Which company is the 
        largest manufacturer of network equipment ?", "IBM", "A: IBM",  "B: 
        CICSO", "C: 
          DELL" , "D: HP"));
        questionModelArraylist.add(new QuestionModel("Which of the following is 
        NOT an operating system ?", "Bios", "A: BIOS", "B: LINUX", "C: WINDOWS" 
        , "D: MAC"));
        questionModelArraylist.add(new QuestionModel("Who is the first cricketer 
        to score an international double century in 50-over match ?", "Sachin 
         Tendulkar", "A: Sachin Tendulkar", "B: Brian Lara", "C: Rohit Sharma" , 
        "D: Rahul Dravid"));
        questionModelArraylist.add(new QuestionModel("Who is the founder of 
        Apple Inc. ?", "Steve", "A: Bill Gates", "B: Steve Jobs", "C: Suresh" , 
        "D: Mark"));

        questionModelArraylist.add(new QuestionModel("Which is the biggest 
        largest city in the world ?", "Reno", "A: Shanghai", "B: Vienna", "C: 
        Reno" , "D: Hong Kong"));


        Collections.shuffle(questionModelArraylist , new Random());
        currentQuestion = questionModelArraylist.get(currentPosition);

        setData();

      //        setUpQuestion();

        submitButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                checkAnswer();
            }
        });



    }
    public void checkAnswer(){
        RadioGroup grp = findViewById(R.id.options);
        RadioButton answer = findViewById(grp.getCheckedRadioButtonId());
        String newAnswer = String.valueOf(answer.getText());

        if(newAnswer.equalsIgnoreCase(questionModelArraylist
        .get(currentPosition).getAnswer())){
                numberOfCorrectAnswer ++;
                Log.d("Score", "Your score: "+            newAnswer);



            new SweetAlertDialog(MainActivity.this, 
       SweetAlertDialog.SUCCESS_TYPE)
                    .setTitleText("Good job! Keep Going")
                    .setContentText("Right Answer")
                    .setConfirmClickListener(new 
       SweetAlertDialog.OnSweetClickListener() {
                        @Override
                        public void onClick(SweetAlertDialog sweetAlertDialog) {
                            currentPosition ++;

                            setData();
       //                            answerEdt.setText("");
                            sweetAlertDialog.dismiss();
                        }
                    })
                    .show();


        }else {

            new SweetAlertDialog(MainActivity.this, 
        SweetAlertDialog.WARNING_TYPE)
                    .setTitleText("Wrong Answer")
                    .setContentText("The right answer is : 
       "+questionModelArraylist.get(currentPosition).getAnswer())
                    .setConfirmText("OK")
                    .setConfirmClickListener(new 
        SweetAlertDialog.OnSweetClickListener() {
                        @Override
                        public void onClick(SweetAlertDialog sDialog) {
                            sDialog.dismiss();

                            currentPosition ++;

                            setData();
       //                            answerEdt.setText("");
                        }
                    })
                    .show();
        }





        int x = ((currentPosition+1) * 100) / questionModelArraylist.size();

        progressBar.setProgress(x);



    }


    public void setData(){


        if(questionModelArraylist.size()>currentPosition) {
       questionLabel.setText(questionModelArraylist
       .get(currentPosition).getQuestionString());
            
      option1.setText(questionModelArraylist.get(currentPosition).getOptA());
            
      option2.setText(questionModelArraylist.get(currentPosition).getOptB());
            
      option3.setText(questionModelArraylist.get(currentPosition).getOptC());
      //            
       option4.setText(questionModelArraylist.get(currentPosition).getOptD());


            scoreLabel.setText("Score :" + numberOfCorrectAnswer + "/" + 
      questionModelArraylist.size());
            questionCountLabel.setText("Question No : " + (currentPosition + 
      1));


        }else{


            new SweetAlertDialog(MainActivity.this, 
       SweetAlertDialog.SUCCESS_TYPE)
                    .setTitleText("You have successfully completed the quiz")
                    .setContentText("Your score is : "+ numberOfCorrectAnswer + 
     "/" + questionModelArraylist.size())
                    .setConfirmText("Restart")
                    .setConfirmClickListener(new SweetAlertDialog.OnSweetClickListener() {
                        @Override
                        public void onClick(SweetAlertDialog sDialog) {

                            sDialog.dismissWithAnimation();
                            currentPosition = 0;
                            numberOfCorrectAnswer = 0;
                            progressBar.setProgress(0);
                            setData();
                        }
                    })
                    .setCancelText("Close")
                    .setCancelClickListener(new 
         SweetAlertDialog.OnSweetClickListener() {
                        @Override
                        public void onClick(SweetAlertDialog sDialog) {

                            sDialog.dismissWithAnimation();
                            finish();
                        }
                    })
                    .show();

        }

     }



   }

     
When i run the program and click on radio button it doesnt take my answer as input instead it always show right answer where i selected correct answer or not. i have an arraylist on the same mainactivity class and model on other class.
It a simple bignner android application.