Which of the following is NOT one of the four major equipment areas?

The correct answer is Testing, as it is not considered one of the four major equipment areas within the context of Gunner's Mate operations. The four major equipment areas are typically focused on systems that involve detection and identification of targets, directing fire, and delivering munitions effectively.

Detection/Identification involves systems that enable the identification of targets and threats, ensuring that operators can accurately assess their environment. Directing pertains to the control and coordination of weapon systems during engagements, ensuring accurate targeting and firing sequences. Delivery refers to the mechanisms and processes used to launch or deliver munitions to targets.

Testing, while important in various operational contexts for ensuring equipment functions correctly, is not classified as a major area like the others that directly contribute to operational effectiveness in a combat scenario.