How can I get selected option in dropdown menu on Ruby on Rails?

Question

How can I know which option in dropdown menu is selected?

<% @quiz.codes.each do |code| %>
    <tr class="quiz_answer" data-code-id="<%= code.id %>">
    <td><%= simple_format code.code %></td>
    <td><%= simple_format code.notes %></td>
    <td><%= form_with(model: [ code, code.student_answers.build ], local: true) do |form| %>
    <p> 
        <%= form.select(:variable_options, code.correct_answers.pluck(:variable, :variable), {prompt: 'Choose variable'}, class: 'answer-variable')%>
        <%= form.select(:role_options, code.correct_answers.pluck(:role, :role), {prompt: 'Choose role'}, class: 'answer-role')%>
    </p>
<% end %>
</td>
</tr>

Answer 1

First of all in above form you used two same fields which is correct_answer_ids so if you remove or change one of them then below code work for you :-

<%= form.select :correct_answer_ids, 
    options_for_select(code.correct_answers.pluck(:variable, :id), form.object.correct_answer_ids),
    {prompt: 'Choose variable'}, { :class => 'answer-variable' } %>