DataClassInfo info = DataClassInfoProvider.GetDataClass("cms.user");
if (info != null)
{
   CMS.FormEngine.FormInfo fi = new CMS.FormEngine.FormInfo(info.ClassFormDefinition);
   // here you need to specify a field
   CMS.FormEngine.FormFieldInfo ffi = fi.GetFormField(<field name>");

   System.Xml.XmlDocument xmlDoc = new System.Xml.XmlDocument();
   xmlDoc.LoadXml("<xml>" + Convert.ToString(ffi.Settings["options"]) + "</xml>");

   System.Xml.XmlNode xmlNode = xmlDoc.FirstChild;

   if (xmlNode.HasChildNodes)
   {
        // loop through all options
        foreach (System.Xml.XmlNode itemNode in xmlNode.ChildNodes)
        {
            // get text/value pair
            string text = CMSContext.CurrentResolver.ResolveMacros(XmlHelper.GetAttributeValue(itemNode, "text"));
            string value = CMSContext.CurrentResolver.ResolveMacros(XmlHelper.GetAttributeValue(itemNode, "value"));
        }
   }
 }