A solution to overcome tripping defects is an arrangement of special plates on either side of the flukes，designed to set them in the correct tripping position. These special plates are called（）.

A.a light sail
B.a topmast stay
C.a sheet
D.standing rigging

A.keep a line from fraying
B.join lines of unequal size
C.stop off a line
D.shorten a line

A.prevents anyone from working the cargo at unauthorized times
B.is a safety measure in case one of the outboard guys parts
C.is a longshoreman who watches for accidents
D.is the same as a blacksmith