Rules of the Road: BOTH INTERNATIONAL & INLAND The term "power-driven vessel" refers to any vessel...

Yep, includes sailing vessels.

I think answer should be (B” because if I’m drifting with my engines off, I’m still a power driven vessel underway.

The answer definitely be B. Underway, but not making way is still a power vessel

A sailboat is only considered power boat when prop is engaged.

Sailing Vessel? Not exactly. It could be a sail BOAT but not a Sailing VESSEL. With propelling machinery in use it is a POWER DRIVE VESSEL as defined by the rules. To be a sailing vessel the states, "...propelling machinery, if fitted, is not being used." When answering NavRules questions always remember to treat the terms as they are defined in the rules.

The vessel described is just a vessel in "B" is just a vessel.

I cant pass this test

Answer is not B because a SAILING VESSEL which has an engine but is under sail power alone will not be considered a power-driven vessel.

Rule 3(b), dont make it more complicated