In which way does SyncE propagate the clocking information in a synchronous mode over an Ethernet link? 

Answer options:

A. It uses the communication channel conveying the clock information that is called SSM
B. It uses broadcast frames
C. It uses dedicated ESMC frames that are sent at regular intervals
D. It encodes the clock information into IEEE1588v2 packets

C

Reference: https://www.cisco.com/c/en/us/td/docs/optical/cpt/r9_7/cpt972_configuration/cpt972_configuration_chapter_010010.html