单项选择题
Navtex transmitter identification character（）is used to identify the broadcasts which are to be accepted by the receiver and those are to be rejected.
A.B2 B.B1 C.MAR D.NNN
单项选择题 The difference between international and national Navtex Service is limited to（）.
单项选择题 A Navtex station in each NAVAREA is usually allowed to have（）for transmission.
单项选择题 It is possible for ships to receive safety message transmitted by Navtex station（）.
