Under the IALA Buoyage Systems, a cardinal mark may NOT be used to __________.

Correct Answer: Option A — indicate the port and starboard sides of well-defined channels

Cardinal marks are specifically designed to indicate the location of hazards relative to the mark, not to delineate the port or starboard sides of a channel. Lateral marks are used for channel boundaries, whereas cardinal marks indicate the safe side to pass a danger based on compass orientation.