What emergency equipment is typically required onboard a bus?

The correct choice highlights the essential emergency equipment that should be present onboard a bus to ensure safety and preparedness in case of an incident. A first aid kit provides necessary medical supplies for attendees in case of injuries, while a fire extinguisher allows the operator to address small fire situations before they escalate. Emergency triangles serve as a warning to other motorists about a disabled vehicle or an emergent situation, aiding in road safety for both the bus and surrounding traffic.

This combination of equipment is comprehensive and ensures that bus operators and passengers are equipped to handle various emergency scenarios effectively. In contrast, having only a fire extinguisher would not cover all potential emergencies, and the inclusion of navigation systems and spare tires does not directly address emergency situations related to health and safety.