直升机商业运行需要通过哪一部法规审定？ Which regulatory approval should be get for

直升机商业运行需要通过哪一部法规审定？ Which regulatory approval should be get for the helicopter commercial operation ?

A.135部 The 135 part

B.121部 The 121 part

C.142部 The 142 part

正确答案是1