Question 603 Rules of the Road

The correct answer is C) over 100 meters at anchor. According to the International Regulations for Preventing Collisions at Sea (COLREGS), vessels over 100 meters in length while at anchor must use both international and inland working lights to illuminate their decks. This requirement ensures that such large vessels are clearly visible to other vessels in the area, enhancing safety and navigational awareness. The other options are incorrect because they do not specify the vessel size or anchoring condition that requires the use of both international and inland working lights.