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.
E