JSFiddle - React, Tailwind, and code Playground

HTML

<select>
  <optgroup label="Cars 1">
      <option value="volvo">Volvo</option>
      <option value="saab">Saab</option>
  </optgroup>
  <optgroup label="Cars 2">
      <option value="mercedes">Mercedes</option>
      <option value="audi">Audi</option>
  </optgroup>
</select>