Which of the following is NOT a basic component of a brake system?

Answer: C — Fluid reservoir

The fluid reservoir is an essential component of a brake system, as it stores the brake fluid necessary for hydraulic systems to operate effectively. This fluid is crucial for transferring force from the brake pedal to the brake components, thus engaging the brakes. In contrast, service brakes, parking brakes, and emergency brakes are all key functional components of a brake system. Service brakes are used during normal driving to stop the vehicle, parking brakes are designed to hold the vehicle stationary when parked, and emergency brakes are intended to be used in situations where the service brakes fail. Understanding the roles of each component helps in recognizing how the entire brake system operates to ensure vehicle safety.