Air Waybill is the most important document in air transportation， the following statements are true in practice（）.

A.It should be issued only by air carrier directly

B.It can be issued by the carrier either directly or through its authorized agent

C.It is anegotiable transport document.

D.It is anon-negotiable transport document

正确答案：It can be issued by the carrier either directly or through its authorized agent； It is anon-negotiable transport document