Which items are included in the demonstration equipment on the CRJ 200?

The correct choice includes the passenger safety card, one demonstration oxygen mask, and one demonstration seatbelt, which are all essential items used by flight attendants during pre-flight safety demonstrations on the CRJ 200. The passenger safety card provides critical information about the aircraft's safety features and emergency procedures, allowing passengers to familiarize themselves with what to expect in the event of an emergency.

The inclusion of one demonstration oxygen mask is vital, as it allows crew members to show passengers how to use the oxygen system in emergencies where cabin pressure loss occurs. Additionally, the demonstration seatbelt is crucial for illustrating the proper way to fasten and unfasten a seatbelt, reinforcing the importance of safety during the flight.

While other options might list helpful safety equipment, they do not align with the specific items designated for passenger demonstrations on this aircraft type. This sets option D apart as the most accurate representation of what is included in the demonstration equipment for the CRJ 200.