What adjustment is crucial for safety when operating a bus?

The correct answer highlights the importance of properly adjusting mirrors for the safe operation of a bus. Proper mirror adjustment is crucial because it maximizes visibility and reduces blind spots, allowing the driver to be more aware of their surroundings, including pedestrians, cyclists, and other vehicles. Good visibility is fundamental to safe driving, especially in a large vehicle like a bus, where maneuverability can be more challenging.

While checking tire pressure is important for vehicle maintenance and ensuring safety, it doesn't directly affect the immediate driving situation as critically as visibility does. Ensuring the doors are locked is also important for passenger safety, but it pertains more to security rather than operational visibility. Maintaining a clean internal environment contributes to overall safety and comfort but is less directly related to the immediate adjustments necessary for safe bus operation.