What is the primary function of the air compressor in an air brake system?

Answer: C — To compress air and store it in air tanks for brakes

The primary function of the air compressor in an air brake system is to compress air and store it in air tanks for brakes. This compressed air is essential for the operation of the air brake system, as it provides the necessary pressure to activate the brakes when needed. When the driver presses the brake pedal, the system uses the stored compressed air to create braking force. Without the air compressor effectively compressing air and ensuring a sufficient supply in the tanks, the brakes would not function properly, leading to impaired braking performance or complete brake failure. In the context of other options, monitoring brake temperature does not involve the air compressor but rather other components. Increasing vehicle speed is unrelated to the function of the air brake system as it is focused on slowing or stopping the vehicle, and applying the brakes manually refers to a different mechanism within the braking system, not the role of the air compressor. Thus, the role of compressing and storing air is crucial for the effective operation of air brakes.