The number of lifeboats on board of Titanic is enough for（)？

材料：

While berthed alongside in Tenerife，the cruise ship Arcadia was carrying out a lifeboat drill．One lifeboat was successfully launched and as it was being recovered，the winch hoisting it failed．The lifeboat was still connected to the falls and it dropped back into the sea. To investigate what had happened，the crew had to wind the falls back onto the winch drum．The lifeboat was disconnected while the crew tried to restart the winch．They were unsuccessful because of a fault on the hand crank cutout switch．

The crew then attempted to wind the falls back on using the hand crank，but because of the time and effort involved，the cutout switch was bypassed and power restored to speed up the operation．The crank handle was left in place． The winch was started．It began to turn and so too did the handle which hit one of the crew over the head．

The investigation found that the winch failed in the first place because the oil used in the winch gearbox was not one recommended．It was too viscose and would have prevented the coupling locking mechanism from operating correctly．

问题：

It was the fault on the ________ that caused the failure to recover the lift boat

A.crank handle

B.hand crank cutout switch

C.power system

D.falls

It was the ________ that hit the crewmember on his head．A.falls

B.hand crank cutout switch

C.crank handle

D.winch drum

The cause of the accident was that ________．A.the oil used in the winch gearbox was too viscose

B.the winch drum was connected with the falls

C.the life boat was too heavy

D.the bypass to the cutout switch was misused by the crew

The lesson from this accident is that ________．A.seafaring is not all about facing unforeseen situations

B.it is not necessary to wear hard hats to prevent sore heads

C.the wrong oil can not have serious repercussions

D.do not start lifeboat winch motors with the crank handle in place

请帮忙给出每个问题的正确答案和分析，谢谢！

()students are playing on the ground.

A. The number of

B. A number of

C. A number