Question 736 Rules of the Road

The correct answer is C) red sidelight. In the illustration D023RR, the arc of visibility labeled "A" represents the arc of visibility of the red sidelight, which is required to be visible from right ahead to 112.5 degrees abaft the beam on the respective side of the vessel, both under the International and Inland Navigation Rules. The other options are incorrect because the stern light and white masthead light have different arc of visibility requirements, and the green sidelight would have a different placement and arc of visibility on the opposite side of the vessel.