function get_cat_options($parentID, $db) {
  $query = 'SELECT * FROM `cat` WHERE `parent` = '. intval($parentID) .';';
  $res = mysqli_query($db, $query);
  ob_start();
  if (mysqli_num_rows($res) > 0) {?>
    <select class="row-item-2 subcat">
        <option value=""><?= 'Категория'?></option>
        <? while ($row = mysqli_fetch_object($res)) {?>
          <option value="<? echo $row->id; ?>"><?  echo $row->name; ?></option>
        <?}?>
    </select>
  <?} else {?>
    <span class="subcat" style="color:green">OK!</span>
  <?}
  return ob_get_clean();
}