Which system may be useful for messages，such as local storm warnings or a shore-to-ship distress alert，for which it is inappropriate to alert all ships in the satellite coverage area?（）

A.Ration food and water supplies
B.Take anti-seasickness pills，if available
C.Determine position and closest point of land
D.Check pyrotechnic supplies

A.Entries relating to pre-voyage，pre-departure and daily tests are required
B.Both A and C
C.All distress，urgent and safety communications must be logged
D.Routine daily MF-HF and INMARSAT-C transmissions do not have to be logged

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