You are approaching another vessel and see that it has the signal flag “O” hoisted．What is your next action（）.

A. Proceed on present course and speed since the vessel is requesting a pilot
B. Attempt to call the vessel on VHF radiotelephone and begin a search because the vessel has a man overboard
C. Attempt to call the vessel on VHF radiotelephone because it is disabled
D. Approach with caution because the vessel is stopped and making no way through the water