Final answer:
The correct answer to the student's question about air brake pre-hill inspection is to ensure there are no audible air leaks and that glad hands and air lines are secure, making options b and c correct.
Step-by-step explanation:
During a pre-hill inspection on a vehicle equipped with air brakes, it is essential to ensure that there are no audible air leaks in the system. Air brakes rely on a constant supply of pressurized air to function correctly, and any leakage could lead to brake failure. Additionally, it is vital to make sure glad hands and air lines are secure since these components are critical for maintaining the integrity of the air supply between the tractor and trailer. Hydraulic leaks are not a concern for an air brake system since they do not utilize hydraulic fluid.