Q
75. Describe what the trailer air supply control does:
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Aa. It is used to supply the trailer with air, shut the air off, and put on the trailer emergency brakes.
Bb. It is a yellow, six-sided knob used to control the tractor protection valve.
Cc. It is a device used to keep the trailer behind the tractor.
Detailed Explanation
The correct answer is "a. It is used to supply the trailer with air, shut the air off, and put on the trailer emergency brakes.". This is based on federal CDL regulations and safety standards.
Correct Answer: a. It is used to supply the trailer with air, shut the air off, and put on the trailer emergency brakes.
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