Dropdown menu not showing. How do I fix it?

Question

https://imgur.com/a/CrV15

You can see the above Imgur album to see what I'm talking about. Basically I can't see what options I have selected in my dropdown menu after selection.

This is my sell.html code:

<div class="form-group">
    <select class="form-group" name="symbol" size="1" required>
        <option disable selected value="">Symbol</option>
            {% for row in rows %}
            {% if row["quantities"] > 0 %}
            <option value="{{ row["stock"] }}">{{ row["stock"] }}</option>
            {% endif %}
            {% endfor %}
     </select>    

Answer 1

Nevermind I fixed it. I changed the select class from form-group to form-control. My CSS was only applying to form-control.