how to use html option tag code example

Example 1: html option

<label for="cars">Choose a car:</label>

<select id="cars">
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
  <option value="opel">Opel</option>
  <option value="audi">Audi</option>
</select>

Example 2: html option

<label for="cars">Choose a car:</label>
<select name="cars" id="cars">
  <optgroup label="Swedish Cars">
    <option value="volvo">Volvo</option>
    <option value="saab">Saab</option>
    <option value="n/a" disabled>unavailable</option>
  </optgroup>
  <optgroup label="German Cars">
    <option value="mercedes" selected>Mercedes</option>
    <option value="audi">Audi</option>
  </optgroup>
</select>