JSFiddle - React, Tailwind, and code Playground

HTML

<td colspan="4">
<input name="discount" type="radio" id="Yes" value="Yes" />Yes
<input name="discount" type="radio" id="No" value="No" />No<br />  
<select class="purple" name="discountselection" id="discountselection" disabled>
<option value="1 Year" selected="selected">1 Year</option>
<option value="2 Years">2 Years</option>
<option value="3 Years">3 Years</option>
</select>                  
</td>

JavaScript

$(function(){
    $('input:radio[name=discount]').one('change', function(){
        $('.purple').removeAttr('disabled');
    });
});