Radar departure control is to terminate the vectoring _______ .
A.at a point where the aircraft can resume its own navigation
B.when the aircraft is clear of all conflicting traffic, is at an appropriate altitude, and the pilot has been advised of his position and given bearing guide the aircraft to a navaid or an appropriate en-route position
C.at an appropriate flight level
D.at the pilot's request or when the controller thinks it is safe for the aircraft to continue the flight procedurally
正确答案是C