BOTH INTERNATIONAL & INLAND A tug is towing three manned barges in line in fog. The third barge of the tow should sound __________.

Correct Answer: Option C — one prolonged and three short blasts

Per COLREGS Rule 35(c), when a tow consists of multiple manned vessels, the last vessel of the tow must sound one prolonged and three short blasts immediately after the tug's signal, identifying the absolute rear extremity of the towline.