BOTH INTERNATIONAL & INLAND Which vessel shall show three lights in a vertical line, the top and bottom being red and the middle being white?

Correct Answer: Option C — A vessel engaged in diving operations

Rule 27(d)(i) mandates that a vessel engaged in diving operations, restricted in her ability to maneuver, must exhibit three all-round lights in a vertical line: red, white, and red. This signal warns other vessels that divers are in the water and the vessel is restricted in its ability to maneuver.