Which of the following does performance OAM defined in PTN devices include?()

A. LM is used to measure unidirectional or bidirectional frame. loss ratio from one MEP to another MEP.

B.DM is used to measure packet transport delay and delay variation from one MEP to another MEP.

C.Experimental (EX) function: send frame. for experiment use in a management domai

D.CSF is used to transmit failure signal at client layer from T-MPLS trail termination source to T-MPLS trail termination sink.

E. loopback link detectio