What is the purpose of seat belts?

The purpose of seat belts primarily revolves around safety. They are designed to hold passengers securely in their seats during a collision, which significantly reduces the risk of injury. In the event of a crash or sudden stop, seat belts prevent occupants from being ejected from the vehicle and help to keep them in a stable position within the car. This containment reduces the severity of injuries by minimizing movement that can lead to impacts with other parts of the vehicle or with other occupants.

While factors like comfort, driver posture, and airbag deployment are relevant to vehicle safety, they do not encapsulate the primary function of seat belts as effectively as the prevention of injury during a collision. Hence, the correct answer highlights the critical safety role that seat belts play in protecting occupants.