JSFiddle - React, Tailwind, and code Playground

HTML

<select id="foo">
    <option selected>a</option>
    <option>b</option>
    <option>c</option>
</select>

<input type="button" id='btn' value="Change to c"/>

JavaScript

$('#btn').click(function() {
    document.getElementById('foo').value = "c";
});