What should you do if your brakes fail while driving?

Answer: B — Pumping the brake pedal and shifting to a lower gear to slow down

If your brakes fail while driving, one of the most effective responses is to pump the brake pedal and shift to a lower gear to reduce your speed. Pumping the brake pedal can sometimes build up enough brake pressure to regain some braking ability, allowing you to slow down effectively. Shifting to a lower gear changes the vehicle's dynamics, using engine braking to help slow the car further. This combination can provide a controlled method to reduce speed in an emergency situation. The other actions, while they may seem intuitive, do not provide the same level of control or safety. For instance, repeatedly honking your horn may alert other drivers but does not address the critical issue of slowing down or stopping the vehicle. Turning off the ignition is dangerous as it can cause a loss of power steering and braking, making the vehicle much harder to control. Lastly, trying to pull the handbrake while maintaining speed can lead to skidding or loss of control if not done correctly, especially in a vehicle equipped with rear-wheel brakes, which could further exacerbate the situation.