BOTH INTERNATIONAL & INLAND A head-on situation at night is one in which you see dead ahead a vessel showing which light(s)?

Correct Answer: Option C — both sidelights of the vessel and her masthead light(s)

Rule 14 defines a head-on situation as one where a vessel sees another ahead and can see both sidelights and masthead lights in a line or nearly in a line. This configuration confirms the vessels are on reciprocal or nearly reciprocal courses, triggering the requirement to pass port-to-port.