Question 501 Rules of the Road

The correct answer is D) All of the above. According to the International Regulations for Preventing Collisions at Sea (COLREGS) and the U.S. Inland Navigation Rules, vessels that are sailing vessels underway, vessels not under command, and vessels restricted in their ability to maneuver while at anchor are all required to sound a fog signal of one prolonged blast followed by two short blasts. This signal is used to indicate the vessel's status and alert other vessels in the vicinity, allowing them to take appropriate actions to avoid a collision. The other options are incorrect because they do not encompass all the vessel types that are required to sound this specific fog signal.