my Rules of the Road reference says B!
Deck
Rules of the Road: BOTH INTERNATIONAL & INLAND A tug is towing three manned barges in line in fog....
Discussing this exam question.
same wtf
I believe it's because it needs to be the last vessel, not the second one, that makes the signal.
Rule 35(e) INTL and 83.35(e) "...the last vessel of the tow, if manned, shall at intervals of not more than 2 minutes sound four blasts in succession, namely one prolonged followed by three short blasts."