What must accompany the oral safety briefing for passengers?

The inclusion of a printed safety card for passengers is essential as it serves as a reference guide that complements the oral safety briefing. This card provides critical information about the aircraft's safety features, emergency procedures, and exits. It enables passengers to have a visual aid that they can refer to throughout the flight, reinforcing the safety instructions given verbally. The printed safety card is designed to ensure that even if a passenger cannot recall all the details from the briefing, they have access to the necessary information to act correctly in the event of an emergency. This is a widely recognized practice in the aviation industry to enhance passenger safety and preparedness.