Which basic code of conduct must you observe in a tunnel?

Your selected combination is correct because all three points are essential rules for driving in a tunnel according to German traffic laws.

1. Driving with dipped headlights, even during the day in a well-lit tunnel, is crucial for visibility and safety. It helps other drivers see your vehicle more clearly, reducing the risk of accidents.

2. Not making a U-turn in a tunnel is important for maintaining a safe flow of traffic and preventing confusion and potential collisions. Tunnels are designed for linear travel, and U-turns can cause significant safety hazards.

3. Following instructions from tunnel personnel is vital, as they are trained to manage traffic and respond to emergencies. Adhering to their guidance ensures both your safety and the safety of others.

Together, these rules promote safe navigation through tunnels and reduce the likelihood of accidents.