How many elevators will run on auxiliary power during fireman's service?

The correct answer is that at least 1 elevator per bank will run on auxiliary power during fireman's service. This is in accordance with safety regulations aimed at ensuring that in the event of a fire or emergency, there are designated elevators that can be utilized for emergency services without putting the occupants at risk.

Fireman's service is specifically designed to provide a safe means of transport for firefighters and emergency personnel in high-rise buildings during a fire incident or similar emergencies. Having at least one elevator operational under auxiliary power ensures that there is a reliable means of access for emergency responders to reach affected floors while minimizing the risk to those still in the building.

Other options suggest either fewer elevators or more than the required number per bank, which can lead to confusion and potentially compromise fire safety protocols. By ensuring that at least one elevator per bank is operational, the systems remain manageable and effective during emergencies, aligning with the outlined safety measures in the Massachusetts State Elevator Code.