When hoisting a boat on gravity type davits using an electric motor driven winch，the davit arms should be brought up（）.

A. to their final position with the winch operating at slow speed
B. to the bar stop，and then hand cranked to their final position
C. until just before they make contact with the limit switch，and then hand cranked to their final position
D. to the embarkation deck，and then hand cranked to their final positio