Final answer:
The service brake system applies and releases the brakes when the driver uses the brake pedal.
Step-by-step explanation:
The brake system that applies and releases the brakes when the driver uses the brake pedal is the service brake system (option A). The service brake system is the primary brake system in a vehicle and is activated by the driver's input on the brake pedal. It uses hydraulic pressure to apply the brakes and bring the vehicle to a stop.