Ah, I think I found it: The
'value' => @$commentonoptions[$lastbeforeid],
decides which is the one selected.
I commented the one out in:
if ($otheranswer['created'] > $lastbeforetime) {
// $lastbeforeid = $otheranswer['postid'];
$lastbeforetime = $otheranswer['created'];
}
Now the question gets selected as default.