The（）is that search and rescue authorities
题型：单项选择题
问题：
The（）is that search and rescue authorities ashore, as well as shipping in the immediate vicinity of the ship in distress, will be rapidly alerted to a distress incident so they can assist in a coordinated SAR operation with the minimun delay.
A.common communication system
B.distress traffic system
C.basic concept of GMDSS
D.SAR operation procedure