Questo e' quello che si riesce a fare

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Untitled</title>

<style>
.ru {background:green; color:#fff; font-family:Arial; font-size:81px;}
</style>

</head>
<body>

<form>
<select>
<option class="ru">Ciao Ciao Ciao</option>
<option>CiaoCiao Ciao</option>
</select>
</form>
</body>
</html>