Score function on python : I have to create a basic 3 question quiz on farming. It needs to ask the 3 questions, output whether you got it correct or incorrect and if you got it incorrect you can try again. It also needs to have a score function.  I have completed the questions and the incorrect/correct part of the specification but no matter what I try I cannot get the score function to work. I have tried:

    score = 0

    def counter(score)
    score = score + 1

    def counter(score)
    score = 0
    score = score + 1

    def counter(score)
    global score
    score = 0
    score = score + 1

and then following that once the answer was correct the line read : 
     
    counter(score)

I have also tried 

    score = 0

then 

    score = score + 1

but nothing is working and I cannot figure out what is going wrong. It also needs to print how many the user got right at the end.

CODE:

    score = 0

    def quiz():
    print("Here is a quiz to test your knowledge of farming...")
    print()
    print()
    print("Question 1")
    print("What percentage of the land is used for farming?")
    print()
    print("a. 25%")
    print("b. 50%")
    print("c. 75%")
    answer = input("Make your choice: ")
    if answer == "c":
       print("Correct!")
       score = score + 1
    else:
        print("Incorrect.")
        answer = input("Try again! ")
    if answer == "c":
        print("Correct")
        score = score + 1
    else:
        print("Incorrect! Sorry the answer was C.")
    print()
    print()
    print("Question 2")
    print("Roughly how much did farming contribute to the UK economy in 2014.")
    print()
    print("a. £8 Billion.")
    print("b. £10 Billion.")
    print("c. £12 Billion.")
    answer = input("Make your choice: ")
    if answer == "b":
        print("Correct!")
        score = score + 1
    else:
        print("Incorrect.")
    answer = input("Try again! ")
    if answer == "b":
        print("Ccrrect!")
        score = score + 1
    else:
        print("Incorrect! Sorry the answer was B.")
    print()
    print()
    print("Question 3.")
    print("This device, which was invented in 1882 has revolutionised farming. What is it called?")
    print()
    print("a. Tractor")
    print("b. Wagon.")
    print("c. Combine.")
    answer == input("Make your choice. ")
    if answer == "a":
        print("Correct!")
        score = score + 1
    else:
        print("Incorrect.")
    answer == input("Try again! ")
    if answer == "a":
        print("Correct!")
        score = score + 1
    else:
        print("Incorrect! Sorry the answer was A.")
    print("You got {0}/3 right!".format(score))

        

