How should an off-airway direct flight be defined on an IFR flig

How should an off-airway direct flight be defined on an IFR flight plan?

A.The initial fix, the true course, and the final fix.

B.All radio fixes over which the flight will pass.

C.The initial fix, all radio fixes which the pilot wishes to be compulsory reporting points, and the final fix.

正确答案是B