The following CSS will right-align both the arrow and the options:
select { text-align-last: right; }_x000D_
option { direction: rtl; }
_x000D_
<!-- example usage -->_x000D_
Choose one: <select>_x000D_
<option>The first option</option>_x000D_
<option>A second, fairly long option</option>_x000D_
<option>Last</option>_x000D_
</select>
_x000D_