JSFiddle - React, Tailwind, and code Playground

HTML

<select class="component" name="blah">
    <option value="1">1</option>
    <option value="2">2</option>
</select>
<select class="component" name="blah2">
    <option value="3">3</option>
    <option value="4">4</option>
</select>
<select name="three"></select>

JavaScript

$('#blah, #blah2').on('change',function() {
    $('#three').empty().append('<option>' + $("#one option:selected" ).text() + '</option>').append('<option>' + $("#two option:selected" ).text() + '</option>');
});