Answer:
The correct answer is A) Essential lighting circuits. According to the web search results, emergency systems are lifelines for people, and they include systems essential to life safety during fires and other disasters, such as fire detectors, alarms, emergency lights, elevators, fire pumps, public safety communication systems, and ventilation systems1. Emergency systems are regulated by a municipal, state, federal, or other government agency. Transfer equipment for emergency systems must be automatic, identified for emergency use, and approved by the authority having jurisdiction (AHJ). It must supply only emergency loads1. Therefore, an emergency transfer switch for emergency systems shall supply only essential lighting circuits, and not HVAC systems, office equipment, or non-emergency outlets.