What should be observed when positioning the head rests in your car?

The correct combination of answers emphasizes proper headrest adjustment for safety. In Germany, as well as in many other countries, the effectiveness of headrests is critical for preventing neck injuries, particularly in the event of a rear-end collision.

Option 1 is essential because having the top of the head level with the upper edge of the headrest helps support the head properly during sudden impacts. It minimizes the distance the head moves backward, which can reduce the risk of whiplash.

Option 2 focuses on minimizing the gap between the head and the headrest. A smaller gap enhances the headrest's protective function by effectively limiting head movement and providing support during an accident.

Option 3 was not selected but is also valid as ensuring that the headrest aligns with the upper neck vertebra is significant for optimal support, which can help prevent neck injuries.

In summary, all three points are interrelated and important for the overall effectiveness of a headrest in protecting occupants during a crash, according to safety regulations and guidelines in German traffic laws. Therefore, understanding and applying all parts of the question contributes to safer driving practices.