Final answer:
To open an oxygen compartment that doesn't open automatically, a manual override lever is used. It serves as a backup to the primary automatic system, ensuring oxygen masks can be deployed in an emergency.
Step-by-step explanation:
If the oxygen compartment does not open automatically, the piece of equipment used to open it is A) Manual override lever. This is a secondary system that is specifically designed to be used when the primary, automatic system fails. In an airplane, for example, there is typically a manual control that can be used to release the oxygen masks if the automatic release does not engage due to a malfunction or other issue. Knowing how to operate emergency systems like manual override levers is part of essential safety training for crew members, and in some cases, its location and usage instructions are also made available to passengers.