Question 3443 Deck General

The correct answer is B) Whenever visibility is restricted. According to the Navigation Rules and Regulations, a mobile offshore drilling unit (MODU) must display navigation lights whenever visibility is restricted, regardless of the time of day. This is to ensure the MODU is visible to other vessels in the area, improving safety and preventing collisions. The other answer choices are incorrect because a MODU is required to display navigation lights at all times when underway, not just when being towed (A), not only between sunrise and sunset (C), and not only when other vessels are in sight (D).