BOTH INTERNATIONAL & INLAND What is TRUE when operating in fog and other vessels are detected by radar?

Correct Answer: Option C — You should maneuver in ample time if a close-quarters situation is developing.

Rule 19(d) requires that if a close-quarters situation is developing, a vessel must take avoiding action in ample time. While radar is a tool for assessment, the primary obligation is to maneuver early and substantially to avoid the risk of collision when targets are detected.