In double/triple trailer operation, brakes are normally controlled by which device?

Answer: B — Foot pedal

Braking in a double or triple trailer setup is controlled by the foot brake pedal. When you press the pedal, air pressure from the tractor’s braking system is sent to apply the service brakes on both the tractor and the trailers, giving you coordinated, proportional stopping. The hand brake lever is for parking or emergencies, not for normal braking. Cruise control maintains speed and does not actuate the brakes, and automatic braking systems aren’t the standard method described here.