Question 3421 Deck General

The correct answer is C) between sunset and sunrise. The United States Code of Federal Regulations (CFR) requires that mobile offshore drilling units on the waters of the U.S. Outer Continental Shelf must display obstruction lights between sunset and sunrise. This is to ensure the visibility of the unit for other vessels and aircraft operating in the area, improving safety. The other answer choices are incorrect because A) displaying the lights at all times is not required, B) the lights must be displayed regardless of visibility conditions, and D) the lights must be displayed between sunset and sunrise, not based on the approach of other vessels.