监控分析按照实现方法的不同分为两种：一种是由数据库建立自动监控机制；另一种是______。

A) 空间管理
B) 管理员手动实现监控
C) 参数调整
D) 查询优化

According to the basic concept of GMDSS,（）can be rapidly alerted to a distress incident.

A.only SAR authorities on land

B.all ships in a very large sea area

C.the nearest coast stations and port radios

D.the SAR authorities ashore as well as ships in the vicinity of the casualty