What must accompany emergency doors on a school bus?

Answer: B — warning signal that is either visible or audible

Emergency doors on a school bus are required to have a warning signal that is either visible or audible. This requirement ensures that when the emergency doors are opened, it alerts others about the situation, enhancing safety for both the children on the bus and any individuals outside. The warning signal serves a critical function by indicating that an emergency situation may be occurring, prompting people nearby to take caution or respond as necessary. The presence of a warning signal plays a crucial role in keeping the environment around the bus safe during emergencies. While it might be beneficial for emergency doors to have other features such as a manual handle or reflective tape, these are not mandated as part of the requirements for safe operation. The focus on a warning signal ensures that safety protocols are followed even in urgent situations.