Who must be wearing a seat belt?
Answer: A — All vehicle passengers
All vehicle passengers, regardless of their position in the vehicle, must be wearing a seat belt. This includes not only the driver and front seat passengers, but also passengers in the rear seat. It is important for everyone in the vehicle to wear a seat belt in order to reduce the risk of injury or death in the event of a crash. Therefore, options B, C, and D are incorrect because they do not encompass all vehicle passengers.