What does "GMT" stand for regarding watches?

The term "GMT" stands for "Greenwich Mean Time," which is a timekeeping standard based on the mean solar time at the Prime Meridian, located in Greenwich, England. In watch terminology, GMT functions as a reference for coordinating time across various time zones. Watches that feature a GMT complication allow the wearer to track multiple time zones simultaneously, making them particularly useful for travelers or those conducting business internationally.

This complication often includes an additional hand on the watch face, which indicates a second time zone by rotating around the dial once every 24 hours, in conjunction with a 24-hour scale. This feature is derived from the fact that GMT represents the mean solar time that is used as a base for calculating time differences around the world.

Other options do not accurately represent a recognized timekeeping system or methodology related to watches, making them incorrect.