Question 123Navigation General

The correct answer is B) north side of the mark. A cardinal mark is a type of navigation buoy or marker that indicates the safest water in relation to the mark. A quick-flashing white light on a cardinal mark means the deepest water is on the north side of the mark. This is based on the International Association of Lighthouse Authorities (IALA) buoyage system, which is the standard used in the United States. The other answer choices are incorrect because a quick-flashing white light on a cardinal mark does not indicate the deepest water is to the west, east, or south of the mark - it specifically indicates the deepest water is to the north.