Which statement concerning the navigation of a vessel in ice is FALSE?（）

A.Anchoring in the presence of ice is not recommended except in an emergency

B.Towing a vessel through an ice field is not recommended except in an emergency

C.The Free and Proceed system of escorting a beset vessel cuts down on the number of freeing operations

D.When anchoring in ice，it is advisable to increase the scope of the chain over what is normally used for non-icing conditions