What should not be done with the inspection port during maintenance?

The correct choice emphasizes that the inspection port should never be left unattended during maintenance. This is crucial because the inspection port serves as an access point for maintenance personnel to perform checks on vital systems. Leaving it unattended could lead to several hazards, including the risk of foreign objects entering the compartment or loss of pressure and system integrity. Additionally, an open inspection port might pose safety risks for personnel working nearby, as it could lead to injuries or accidents if someone inadvertently interacts with machinery exposed through the port.

In maintenance practices, it is essential to keep work areas safe and monitored. Proper supervision ensures that any issues can be addressed immediately, maintaining both the safety of the crew and the integrity of the craft.