WML <optgroup> tag

<select>
 <optgroup>
  <option>text</option>
  <option>text</option>
 </optgroup>
  <optgroup>
  <option>text</option>
  <option>text</option>
 </optgroup>
</select>

<?xml version="1.0"?>
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN"
"http://www.wapforum.org/DTD/wml_1.1.xml">

<wml>
<card title="Selectable List"> 
<p>
 <select>
   <optgroup title="HTML Tutorials">
    <option value="html">HTML Tutorial</option>
    <option value="css">CSS Tutorial</option>
    <option value="dhtml">XHTML Tutorial</option>
   </optgroup>
   <optgroup title="XML Tutorials">
    <option value="xml">XML Tutorial</option>
    <option value="xsl">XSL Tutorial</option>
    <option value="xforms">XForms Tutorial</option>
   </optgroup>
 </select>
</p>
</card>
</wml>