单项选择题
The difference between international and national Navtex Service is limited to（）.
A.frequency allocated B.both language and frequency C.language used D.transmission power and time
单项选择题 A Navtex station in each NAVAREA is usually allowed to have（）for transmission.
单项选择题 The NAVTEX receiver can be mounted on（）.
单项选择题 The concept of NAVTEX is of a（）system for the broadcast and receipt of MSI.
