HTML Question - form> select> option> background color

Hi

In the following simple form - How do you force the <select> tag to take on the background color of the selected <option> tag when a selection has been made?

<form>
	<select>
		<option style="background-color:#FF0000">how</option> 
		<option style="background-color:#00FF00">why</option> 
		<option style="background-color:#0000FF">who</option> 
	</select>
</form>

HTML:

Thanks