JSFiddle - React, Tailwind, and code Playground

HTML

<select name="" id="a">
    <option value="0">Select</option>
    <option value="1">Milk</option>
    <option value="2">Eggs</option>
    <option value="3">Cheese</option>
    <option value="4">Butter</option>
    <option value="5">Pizza</option>
</select>
<select name="" id="b">
    <option value="0">Select</option>
    <option value="3">Milk</option>
    <option value="5">Eggs</option>
    <option value="9">Cheese</option>
    <option value="8">Butter</option>
    <option value="10">Pizza</option>
</select>

CSS

* {font-family: sans-serif; text-decoration: none; font-size: 0.9em;}

JavaScript

$(document).ready(function(){
    var a, b;
    $("#b").prop("disabled", false);
    $("#a").change(function(){
        a = $(this).val();
        $("#a").a.val("3");
        $("#b").prop("disabled", true);

      /*  $("#b").prop("disabled", false); */
    });
});