Change Text Color of Selected Option in a Select Box

.greenText{ background-color:green; }

.blueText{ background-color:blue; }

.redText{ background-color:red; }

<select
    onchange="this.className=this.options[this.selectedIndex].className"
    class="greenText">
     <option class="greenText" value="apple" >Apple</option>
    <option class="redText"   value="banana" >Banana</option>
    <option class="blueText" value="grape" >Grape</option>
</select>