Which item must be checked for security during the preflight inspection on the ERJ 175?

The correct answer emphasizes the importance of ensuring that safety equipment is secured and functioning properly before flight operations. The megaphone is typically a critical safety device onboard, primarily used in emergencies to communicate with passengers. During the preflight inspection, it’s essential to confirm that this device is present, secure, and operational, as it can play a vital role in emergency situations.

While other items such as the passenger cabin, first aid kit, and service cart are also important and require checks, the specific focus on the megaphone indicates its unique role in direct passenger communication during emergencies. Ensuring that safety equipment, like the megaphone, is adequately checked is crucial for maintaining flight safety protocols.