Marina Exam Reviewer: Which signal, other than a distress signal, can be used by a vessel to attract attention?

Marina Exam Reviewer

Which signal, other than a distress signal, can be used by a vessel to attract attention? 

A. Searchlight beam 
B. Burning barrel 
C. Continuous sounding of a fog signal apparatus 
D. Calling "Mayday" on the radiotelephone 


Answer:  A. Searchlight beam