What is the basic concept of GMDSS? （）

A.Search and rescue authorities ashore can be alerted to a distress situation

B.Shipping in the immediate vicinity of a ship in distress will be rapidly alerted

C.Shoreside authorities and vessels can assist in a coordinated SAR operation with minimum delay

D.All of the above

在算法的4个特性中，算法必须能在执行有限个步骤之后终止指的是算法的______特性。