How many PBEs are installed in the cabin of the ERJ 175 aircraft?

The correct answer is that there are three Personal Breathing Equipment (PBE) units installed in the cabin of the ERJ 175 aircraft. This ensures adequate safety measures for the crew and passengers in case of a smoke-filled cabin or emergency situations where supplemental oxygen is necessary.

Having three PBEs allows for efficient distribution among the crew, catering to immediate needs in the event of an emergency. The placement of the PBEs is strategically done to ensure quick access from various parts of the cabin, promoting prompt response during critical situations. This standard equipment aligns with safety regulations, ensuring that the crew is well-equipped to handle emergencies while minimizing potential hazards to passengers.

This setup is a crucial aspect of cabin safety protocols, thus illustrating why three units are installed, as they play a significant role in the emergency preparedness of the aircraft. Other choices do not reflect the established safety equipment standards for the ERJ 175, which prioritize providing sufficient resources for cabin crew in emergencies.