What should you do if your brakes fail while driving?

Answer: B — Shift to a lower gear and pump the brakes

When faced with brake failure while driving, shifting to a lower gear and pumping the brakes is a critical response. This technique helps to slow the vehicle down gradually, as reducing gears allows the engine to create resistance against the vehicle's motion, aiding in deceleration. Pumping the brakes may also build up brake pressure if there's still some function in the braking system, which can potentially help bring the vehicle to a stop. Turning off the engine can lead to loss of steering control and may disable power-assisted brakes, making it more difficult to control the vehicle. Pressing the gas pedal harder would only accelerate the situation and potentially lead to a more dangerous scenario. Finally, immediately pulling into traffic is hazardous; it not only puts you at risk but could also endanger other drivers by creating an unpredictable situation on the road. Thus, the most effective and safest response during a brake failure is to shift to a lower gear and pump the brakes.