INTERNATIONAL ONLY In a narrow channel, an overtaking vessel which intends to PASS on the other vessel's port side would sound __________.

Correct Answer: Option D — two prolonged followed by two short blasts

Under COLREG Rule 9(e)(i), when navigating in a narrow channel or fairway, an overtaking vessel intending to pass on the other vessel's port side indicates this specific operational intent by sounding two prolonged blasts followed by two short blasts.