When a driver performs an emergency brake in a vehicle equipped with ABS, the brake pedal begins to pulsate rapidly against their foot with a vibrating mechanical noise. What should the driver do?

1. Immediately release the brake pedal because the braking system has failed
2. Maintain continuous, firm, hard pressure on the brake pedal while steering to safety (保持用力踩住制动踏板不放)
3. Pump the brake pedal manually on and off repeatedly
4. Shift the transmission into Neutral and pull the mechanical handbrake sharply