Q
93. The trailer air supply control (also known as the tractor protection valve control) should automatically close when the air pressure falls to between:
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Aa. 60 and 80 psi.
Bb. 45 and 60 psi.
Cc. 20 and 45 psi.
Detailed Explanation
The correct answer is "c. 20 and 45 psi.". This is based on federal CDL regulations and safety standards.
Correct Answer: c. 20 and 45 psi.
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