单项选择题
With respect to automatic identification systems（AIS），which information is required to be broadcast every 1 to 10 seconds（）.
A.Call sign and IMO number B.Course over ground and MMSI C.MMSI number and call sign D.Route Plan and navigational status
单项选择题 While you are at anchor，what will serve as a positive warning that you are drifting towards the wrecks located to the NW and SW of your 2215 position（）.
单项选择题 Which statement concerning GPS is TRUE（）.
单项选择题 Which one of the followings does not limit the effective range of radar（）.
