The registration options and preferences available when you add registrants are tied to the options you set up on the Event record.  

Steps to Resolve:
  1. Go to the Event Record and click on the Options tab
  2. Add the necessary Registration Options and Preferences.
  •  Note: If you do not have any Registration Types to select when setting Registration Options, you'll need to add these through the Configuration menu in the Events section.
  1. After adding your Options, proceed with adding event registrants