What is the legal requirement regarding seat belts in a vehicle?

The legal requirement regarding seat belts in a vehicle mandates that all passengers must wear seat belts. This rule is in place to ensure the safety of everyone in the vehicle during travel. Seat belts are one of the most effective safety features in automobiles, significantly reducing the risk of injury or fatality in the event of a collision.

By requiring all passengers to secure their seat belts, the law helps protect not only the occupants of the vehicle but also can reduce the likelihood of being ejected from the vehicle in an accident, which can lead to severe injuries. Additionally, having all passengers buckled up can prevent distraction for the driver, as unsecured passengers can move around during driving, which may lead to accidents.

The other options suggest varying degrees of seat belt use that do not align with the law. Limiting the requirement to just the driver or front-seat passengers would exclude rear-seat passengers and undermine overall safety. Additionally, indicating that seat belts are optional for adults ignores the established regulations that apply uniformly to all vehicle occupants, regardless of age. Thus, the correct answer highlights the comprehensive nature of the seat belt law for maximum safety.