单项选择题
In NAVTEX service, the subject indicate character B means（）.
A.meteorological warnings B.navigational warnings C.search and rescue information D.meteorological forecast
单项选择题 NAVTEX transmissions have a designed range of about（）nautical miles.
单项选择题 The NAVTEX receiver can be mounted on（）.
单项选择题 Ships at sea are in urgent need of MSI because they are（）various kinds of danger.
