JSFiddle - React, Tailwind, and code Playground
HTML
<select class="assUnit">
<option>Unit1</option>
<option>Unit2</option>
<option>Unit3</option>
</select>
<select class="assUnit">
<option>Unit10</option>
<option>Unit2</option>
<option>Unit33</option>
</select>
<input type="button" id="my_button" value="test me"/>
JavaScript
$(function(){
$('#my_button').click(function(){
var unitName = "Unit2";
$(".assUnit option").filter(function() {
return $(this).text() == unitName
}).remove();
})
});