BOTH INTERNATIONAL & INLAND You see the display of lights shown in illustration D071RR below. What do these lights indicate?

Correct Answer: Option B — a vessel approaching head-on

Rule 23(a) dictates that a power-driven vessel underway shall exhibit a masthead light forward, a second masthead light abaft and higher than the forward one, sidelights, and a stern light. Seeing these lights vertically aligned indicates the vessel is approaching head-on, showing both sidelights and masthead lights simultaneously.