Explanation: Survival Craft Transceiver (SCT) batteries, commonly found in devices like Survival Craft VHF handheld radios or SARTs (Search and Rescue Transponders), are critical safety equipment for maritime distress situations. To ensure their reliability when needed most, international maritime regulations, specifically those under SOLAS (Safety of Life at Sea) as implemented by the FCC, mandate strict maintenance schedules. These specialized primary batteries are designed for a long shelf life. The regulation requires them to be replaced every five years, or immediately after any use for distress communications. This 5-year interval balances the battery's expected operational lifespan with the need to guarantee full power output and reliability in an emergency. Options A, B, and D are incorrect as they do not align with these crucial safety regulations.