Rules of the Road: INLAND ONLY You have made your vessel up to a tow and are moving from a pier out...

One prolonged and two short (answer D) is covered in Rule 35 “Sound Signals in Reduced Visibility”. This question is referring to INLAND Rule 34 (g) “When a power driven vessel is leaving a dock or berth, she shall sound one prolonged blast”

I thought it was one prolonged blast..?

It is !!