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