Which statements are correct about the clock planning principle? ()

A.The line clock tracing should follow the minimum path requirement.

B.The clock compensation should be given if there are many nodes on the link and each of them extracts the clock from a distance to the near.

C.It is suggested that SSM protocol is used in the whole network (user-defined mode II) to provide clock protection and avoid clock looping.

D.For the clock synchronization scheme of CES service, the PE synchronization mode is the first choice and the adaptive mode is the second choice.