That particular solution was for actual fields on a form and not for variables. This is mostly because it was for a record producer. Do you know if you are using a record producer, or a catalog item? If it is an actual catalog item, ServiceNow may have ways of getting at the selected values better than what was provided. There is an existing Notification email script that is used for this purpose that you can pull from called: requested_items_summary_with_options.