JSFiddle - React, Tailwind, and code Playground

HTML

<select id="choose">
  <option value=1>A</option>
  <option value=2>B</option>
  <option value=3>C</option>
</select>

<div id="hide-me">hide me!</div>

JavaScript

document.querySelector('#choose').addEventListener('change', function () {
    var element = document.getElementById('hide-me');
    if (this.value === "2") {
        element.style.display = 'none';
    } else {
        element.style.display = 'block';
    }
});