C# selenium. pls help me : First of all, Im not good at English. I want u to understand it.
Im programing selenium of c#. but I dont understand howto useit;/
For example,I want to check the XPath that I want to click from HTML.
This is the HTML Iwant.

    <span class="option_text">10</span>

Below is the original HTML
-----

    <div class="report_options _options">
    <a href="#" class="option" data-reportpolicy="R1">
        <i class="ico as_radio"></i>
            <span class="option_text">1</span>
    </a>
    
    <a href="#" class="option" data-reportpolicy="R2">
        <i class="ico as_radio"></i>
          <span class="option_text">2</span>
    </a>
    .
    .(Omitted)
    .
    <a href="#" class="option" data-reportpolicy="R11">
        <i class="ico as_radio"></i>
            <span class="option_text">10</span>
    </a>
</div>



I used

    WebDriver.FindElement(By.XPath("//span[contains(@class,'option_text') and contains(text(), '10')]")).Click();
but I could not.
Someone give me advice pls. 