Rules of the Road: INTERNATIONAL ONLY You are in sight of another vessel in a crossing situation, a...

If you are the stand-on vessel, wouldn't this mean the other vessel was turning into your path?

I agree with Beluga, I'm confused why this isn't C. If I'm holding course and speed, doesn't that mean I'm the stand-on vessel? And doesn't one short blast mean the other vessel, to my port, is making a turn to starboard, towards me?

Disco, yes, this question implies that you are the stand on vessel, so it is safe to assume the give way vessel is to your port side. By Rule 15 (Crossing Situation), IF the give way vessel is a Power Driven Vessel, they should avoid crossing ahead of you. So, they should not speed up or turn left to cross ahead of you, and it is therefore reasonable that they would alter their course to their right so as to pass behind you, and under international rules, they sound one short when altering course to starboard, and you are not required to answer that signal. IF they don't turn sharply or enough so that you are confused as to what they are doing, then Rule 34 kicks in and requires you to sound 5 short.