材料：MV Magellan was inbound from Rotterdam to berth 207 at Southampton Container Terminal

材料：

MV Magellan was inbound from Rotterdam to berth 207 at Southampton Container Terminal．At 0530 the pilot boarded the ship at the Nab Tower pilot station．The pilot&39;s and the master&39;s passage plans were exchanged and the ship&39;s pilot card was given to the pilot．

The passage continued along the East Solent，during which time there were various VHF radio conversations between vessels and Southampton VTS，about restricted visibility．The VTS officer gave the pilot a countdown from 5 to 2 cables to the Gurnard buoy．This was given so that the pilot could judge the timing of the wheel-over manoeuvre for the 141° turn into the narrow Thorn Channel．The wheel-over occurred at about 0652 and the ship began to turn．

At this time，the W Bramble and NE Gurnard buoys，which are at the entrance to Thorn Channel，could not be seen because of restricted visibility．Various helm and engine movements were made during the turn．However，when W Bramble and NE Gurnard buoys appeared，the pilot realized that the ship was in the wrong position for the heading she was on．Despite further helm and engine orders，the vessel grounded soon after，at 0700．It was not until about 0710 that the escort harbor launch informed VTS of the grounding．With the assistance of two tugs，the ship was refloated near the time of high water，and she safely berthed at 1232．

问题：

MV Magellan applied wheel at ________ to turn into the narrow Thorn Channel．

A.0530

B.0652

C.0700

D.0710

The important navigational mark or marks at the entrance to the Thorn Channel is（are）________．A.Southampton Container Terminal

B.the East Solent

C.the Nab Tower

D.the W Bramble and NE Gurnard buoys

The suggestion of a countdown from 5 to 2 cables to the Gurnard buoy is ________．A.for the pilot to judge easily when the wheel should be used to make the turn into the narrow Thorn Channel

B.to remind the pilot that the depth around there is not sufficient for MV Magellan

C.to inform the pilot that the visibility around the buoy is reduced further

D.to request the pilot that further consideration should be given to the wheel-over manoeuvre for the 141° turn

It can be concluded that the cause of the grounding was that ________．A.the Bramble and NE Gurnard buoys were disappeared

B.the VHF radio conversations between vessels and Southampton VTS，about restricted visibility，were insufficient and improper

C.Thorn Channel was too narrow

D.there was an error of judgment by the pilot during the execution of the turn into Thorn Channel

请帮忙给出每个问题的正确答案和分析，谢谢！