Marina Exam Reviewer: What whistle signal, if any, would be sounded when two vessels are meeting, but will pass clear starboard to starboard?

Marina Exam Reviewer

What whistle signal, if any, would be sounded when two vessels are meeting, but will pass clear starboard to starboard? 

A. Two short blasts 
B. One short blast 
C. Five or more short blasts 
D. No signal is required. 

Answer:  D.  No signal is required.