If your brakes fail while driving, what should you do first?

Answer: B — Pump the brake pedal several times

When your brakes fail while driving, the most appropriate first action to take is to pump the brake pedal several times. Pumping the brake pedal can often help restore some brake function by building up hydraulic pressure in the braking system. This may give you enough stopping power to slow down and bring the vehicle to a safe stop. Applying the parking brake immediately (Option A) might cause the vehicle to skid, especially at high speeds. Switching to a lower gear (Option C) can help slow down the vehicle, but it is not as effective as pumping the brake pedal. Turning off the engine (Option D) should be a last resort after you have tried other methods as it will make steering more difficult.