What must emergency exits on a school bus have?

Answer: B — visible and audible warning device

Emergency exits on a school bus must be equipped with a visible and audible warning device to ensure the safety of passengers, particularly in emergency situations. The presence of such devices serves multiple purposes: they alert passengers and any individuals outside the bus to the potential need for evacuation, clearly indicating the locations of exits. This is crucial in maintaining order and facilitating a swift response during emergencies, where time is often of the essence. In contrast, a visible but non-audible warning—though it may provide some indication—does not effectively communicate urgency or attract attention when it is most needed. Relying solely on a manual opening mechanism for emergency exits would also not be sufficient, as evacuating passengers need to be informed quickly and efficiently about how to use these exits in a time-sensitive scenario. Lastly, there are indeed specific safety requirements for emergency exits on school buses, dismissing the idea that there are no regulations governing these critical safety features. Thus, having both visible and audible warnings aligns with safety standards and best practices in student transportation.