An advantage of using chain lashing on heavy vehicles aboard Ro-Ro vessels is that it（）.

A.increase the towing hawser's catenary and provide more spring
B.reduce catenary，allow operation in shallower water，and to release one barge without breaking up the entire tow
C.enable one tug and its crew without any outside assistance to make up or break down the tow
D.provide rapid delivery of logs from the northwestern United States to Hawaiian sawmills

A.only when the load is taken off the cable
B.only when there is a load on the cable
C.only when activated by the controls at the lowering station
D.at any time

A.Cirrus
B.Cumulus
C.Stratus
D.Nimbus