Why is a warning sign displayed at the gangway or access point of a barge during cargo transfer（）.

A.Electrical wiring
B.Iron pipe
C.Radio
D.All of the above

A.Let the anchor fall free from the hawsepipe，but apply the brake at intervals to check the rate of fall
B.Back the anchor slowly out of the hawsepipe a few feet，and then let it fall in the normal fashion
C.Let the anchor fall off the brake right from the hawsepipe，but keep a slight strain on the brake
D.Under power，back the anchor out until it is near，but clear，of the bottom before letting it fall

A.Light List
B.Notice to Mariners
C.Coast Pilot
D.Sailing Directions