Which of the following statements about the principle of SmartLink & Monitor Link is correct?

Which of the following statements about the principle of SmartLink & Monitor Link is correct?
A . SmartLink is a port linkage solution that monitors the device uplink. The Up/Down status change of the uplink triggers the Up/Down change of the downlink.
B . MonitorLink implements redundant backup of the primary and backup links, and enables traffic to be quickly switched to the backup link when the primary link fails.
C . MonitorLink sends Flush messages to notify other devices to refresh the MAC address forwarding table and ARP table entries.
D . SmartLink sends Flush messages to notify other devices to refresh MAC address forwarding entries and ARP entries.

Answer: D