JSFiddle - React, Tailwind, and code Playground

HTML

<select id="id">
    <option>foo</option>
    <option>bar</option>
    <option>baz</option>
</select>

CSS

select { font-size:50px; }

JavaScript

$('#id option').slice(-1)[0].customProp = 'customValue';

$('#id option:[customProp="customValue"]').attr('selected', true);