You are approaching another vessel and see that she has the signal flag “J” hoisted. What should you do?（）

A. Keep well clear of the vessel because she is on fire and has dangerous cargo on board or she is leaking dangerous cargo
B. Attempt to call the vessel on VHF radiotelephone because she is requesting to communicate
C. Approach the vessel with caution because she is dragging her anchor
D. Proceed on present course and speed since the vessel is requesting a tug