JSFiddle - React, Tailwind, and code Playground

HTML

<select id="select1">
<option>Choose One</option>
<option value="1">Val 1</option>
<option value="2">Val 2</option>
<option value="3">Val 3</option> 
</select>

<select id="select2">
<option>Choose Two</option>
<option value="1">Val 1</option>
<option value="2">Val 2</option>
<option value="3">Val 3</option> 
</select>

CSS

#select2{
    display: none;
}

JavaScript

$("#select1").change(function(){
    if($(this).val() == 3){
      $("#select2").show();
    }else{
      $("#select2").hide();
    }
    
});