A U.S. Coast Guard icebreaker, while escorting ships in ice, may sound four short and one long blasts on the whistle to indicate that the icebreaker __________.

Correct Answer: Option D — has become beset in fast ice

Maneuvering and warning signals in ice designate four short and one long blasts on the whistle as the standard audio signal indicating that the icebreaker has become beset in fast ice and cannot make further headway.