单项选择题
If a ship station relays a DSC distress call to an appropriate coast station, it means that（）.
A.the ship has received the DSC distress call on a HF frequency B.the coast station concerned has not acknowledged it within 5 minutes C.the ship will take command of search and rescue in 5 minutes D.A and B
单项选择题 After has permit the commissioning, the（）will permit the SES access to system.
单项选择题 There are（）NCSs in total, one in each ocean region, the AOR (E and W), IOR and POR.
单项选择题 The NCC is located in the（）.
