Final answer:
In case of brake failure, downshift to utilize engine braking, apply your emergency brake smoothly, steer to safety, and use your hazard lights to signal distress. Once stopped and safe, then call 911 for assistance.
Step-by-step explanation:
If your brakes fail, the correct response is to downshift and find an escape route (Option A). This action allows you to gradually slow down the vehicle using engine braking. Immediately engage your emergency brake in a controlled manner to avoid skidding, and try to steer your car safely off the road. It is also wise to turn on your hazard lights to alert other drivers that you're experiencing difficulties. Although not listed in your options, pumping the brake pedal could also help to build up enough pressure to stop the vehicle. Calling 911 (Option B) is advisable once you have come to a stop and are in a safe location, rather than trying to have them clear the highway. Honking your horn and flashing your lights might be useful to signal distress to other drivers, but safety measures to slow down the car are critical and should be the priority. Cranking the wheel 180 degrees is dangerous and could cause you to lose control of your vehicle, so it should be avoided.