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单选题
In the United States, flight information service to flights not requiring ATC service is normally provided by flight service stations, （ ） some cases this service is also provided by aerodrome control towers. FSS accept（ ）, provide pre-flight briefing both as regards MET and AIS and provide normal FIS to aircraft in flight.
A
at, plan
B
on, airplane
C
in, flight plans
D
in, airplanes
答案解析
正确答案：C
