Question 729 Rules of the Road

The correct answer is D) green sidelight. In illustration D023RR, the arc of visibility shown by item "B" corresponds to the green sidelight, which is required to be visible from dead ahead to 112.5 degrees abaft the beam on the starboard side of the vessel, as per the navigation rules. The other options are incorrect because the red sidelight (A) has a different arc of visibility, the white masthead light (B) is not a sidelight, and the stern light (C) has a different placement and arc of visibility compared to the green sidelight shown in the illustration.