If there are red flashing lights above all motorway lanes, what should you do?

Answer: B — Stop and wait

In this scenario, red flashing lights above all motorway lanes indicate that there is a serious emergency or hazard ahead and it is necessary to stop and wait until it is safe to proceed. Continuing with caution may put you at risk of entering a dangerous situation. Speeding up to clear the area could be dangerous for you and other drivers, and turning around would not be a suitable option in a motorway as it goes against the flow of traffic. Therefore, the best course of action is to follow the instructions of the flashing lights and come to a complete stop to ensure your safety and the safety of others.