What arm should you place on the back of the driver's seat?

Answer: B — Right arm

Placing your right arm on the back of the driver's seat is a common practice that helps improve your visibility and control while driving. This position allows you to turn your upper body to better see the road or traffic conditions behind you when you need to look over your shoulder while changing lanes or merging. Using your right arm also allows for a more comfortable posture, as your left arm remains focused on the steering wheel and maintains control of the vehicle. Keeping the correct hand positions while driving is crucial for safety, as it allows for quick reactions to any unforeseen circumstances. The wrong methods suggested would hinder visibility or control, such as placing both arms in a way that does not support safe driving or the instinctive actions needed while on the road. Thus, using your right arm on the seat back strikes a balance between comfort and safe driving practices.