During a pre-trip inspection, when should a driver test the trailer parking brake function?

During a pre-trip inspection, when should a

Multiple choice — select the best answer

ABy applying the service brakes and listening for air leaks
BBy checking if the trailer brake hand valve functions
CBy visually inspecting the trailer brake chambers only
DBy releasing only the tractor parking brakes and attempting to pull forward gently

✓ Correct answer: D. By releasing only the tractor parking brakes and attempting to pull forward gently The trailer parking brake should be tested during a pre-trip inspection by releasing only the tractor parking brakes while keeping the trailer parking brakes applied. Then attempt to pull forward gently. This verifies that the trailer brakes are functioning and can hold the combination vehicle.

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During a pre-trip inspection, when should a driver test the trailer parking brake function?

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