In aerial photography flight, the safety altitude between the aircraft and obstacles in mountainous areas should not be less than _______ m.
A.100
B.200
C.300
D.400
正确答案是B
In aerial photography flight, the safety altitude between the aircraft and obstacles in mountainous areas should not be less than _______ m.
A.100
B.200
C.300
D.400
正确答案是B