单项选择题
A.only SAR authorities on land
B.all ships in a very large sea area
C.the nearest coast stations and port radios
D.the SAR authorities ashore as well as ships in the vicinity of the casualty
单项选择题 Stations in the United States of America are grouped by states arranged in the alphabetical order of their（）.
单项选择题 At least（）two-way VHF radiotelephone apparatus shall be provided on every cargo ship of 300 tons gross tonnage and upwards but less than 500 tons gross tonnage.
单项选择题 Every lifeboat which is fitted with a fixed two-way VHF radiotelephone apparatus with（）which is separately mounted shall be provided with arrangements for sitting and securing the antenna effectively in is operating position.