What should be checked regarding the bus's lights?

When conducting a pre-trip inspection on a bus, it is crucial to ensure that all lighting systems are functioning properly for safety and compliance. This includes not just the headlights, but also the signal lights, brake lights, and marker lights. Each of these illuminations plays a vital role in communication with other drivers and ensuring visibility on the road.

Signal lights indicate turns and lane changes, brake lights alert other drivers when the bus is slowing or stopping, and marker lights provide visibility and identification of the bus’s dimensions, especially in low-light conditions. A thorough check of all lights helps prevent accidents and ensures the bus is roadworthy, making option B the most comprehensive and safe choice.

In contrast, the other options suggest limited checks, which would increase the risk of malfunctioning lights going unnoticed, potentially leading to dangerous situations while driving.