BOTH INTERNATIONAL & INLAND In illustration D023RR below item "B" shows the arc of visibility of which of the following lights?

Correct Answer: Option D — green sidelight

Rule 21(b) defines sidelights as a green light on the starboard side and a red light on the port side, each showing an unbroken light over an arc of the horizon of 112.5 degrees. Item "B" represents this starboard green sidelight arc.