Adding error with php in option list
===

Code below is part of cart66 WordPress plugin's php file. When I list options of my items for example, 

T-shirt
Quantity: 1
Option: Red, Yellow, Blue

First option is always what I put first in the list. Therefore, when my customers don't pay an attention and add to cart without looking at the list they order red. I added "Please choose a pattern" option at the top but they still add that to cart and checkout. Is there a way of adding an option and making it give an error in case that option is selected ?

      private function _buildOptionList($optNumber) {
        $select = '';
        $optionName = "options_$optNumber";
        if(strlen($this->$optionName) > 1) {
          $select = "\n<select name=\"options_$optNumber\" id=\"options_$optNumber\" class=\"cart66Options options_$optNumber\">";
          $opts = split(',', $this->$optionName);
          foreach($opts as $opt) {
            $opt = str_replace('+$', '+ $', $opt);
            $opt = trim($opt);
            $optDisplay = str_replace('$', CART66_CURRENCY_SYMBOL, $opt);
            $select .= "\n\t<option value=\"" . htmlentities($opt) . "\">$optDisplay</option>";
          }
          $select .= "\n</select>";
        }
        return $select;
      }