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

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 conditio