—          that he managed toget the information?

— Oh, a friend of his helped him.   [ ]

A. Where was it    

B. What was it

C. How was it    

D. Why was it

PON是以点到多点为特征的单纤双向无源光网络，它不包括（）。

A.OLT

B.ONU

C.BAM

D.ODN