What should be checked as part of a pre-trip inspection on a combination vehicle?

The correct choice involves checking the tires, brakes, lights, and connections as part of a pre-trip inspection on a combination vehicle because these components are critical to the safety and functionality of the vehicle.

During a pre-trip inspection, it is essential to ensure that the tires are in good condition, have adequate tread depth, and are properly inflated to handle the weight of both the tractor and the trailer. Inspecting the brakes is vital, as they must function effectively to stop the combination safely under various conditions. The lights must also be operational, including turn signals and brake lights, to ensure visibility and communication with other drivers on the road. Checking the connections between the tractor and trailer—such as the fifth wheel, safety chains, and electrical connections—is crucial for preventing any separation or malfunction while driving.

Focusing solely on just the engine temperature, trailer brakes, or even the stereo system does not address the comprehensive safety needs required when operating a combination vehicle. Each of these other components could lead to significant safety hazards if not properly inspected before driving.