The inability to supply a cargo of the contractual quantity in the country of shipment（）the doctrine of frustration into operation.

A.ships arrive at random
B.cargo-handling time varies greatly
C.ships have to queue to get onto berths
D.ships do not have to wait to get onto berths

A.breakdown
B.breaked down
C.broken down
D.broke down

A.decelerating when lowering the load
B.decelerating when raising the load
C.lowering the load at constant speed
D.raising the load at constant speed