At night you see, dead ahead and closing, both a red and a green sidelight and two white masthead lights in a vertical line. Which COLREGs rule applies, how do you know the situation is head-on, and what does Rule 14(c) require if you are in any doubt?

1. Rule 14 applies: seeing both sidelights and the masthead lights in line is the presumption of a head-on meeting, and Rule 14(c) requires that if there is any doubt whether such a situation exists you shall assume that it does and act accordingly — alter course to starboard and pass port to port
2. Rule 13 applies, because two white lights in line always mean you are overtaking
3. Rule 14 applies, but where there is doubt you should hold your course and speed until the aspect resolves itself
4. Rule 15 applies, because seeing a green light on your bow always makes you the stand-on vessel