For Michigan CDL air-brake testing, you are driving down a steep grade and your brakes start to fade. What is the SAFEST immediate response?

1. Pump the brakes faster
2. Look for a safe place to pull off, downshift to maximum engine braking, use any retarder, and find a runaway ramp if you cannot regain control
3. Apply the parking brake at speed
4. Speed up to clear the grade