What is the correct statement about the ip-link feature?

ip-link is a function to detect link connectivity

ARP detection mode only supports detecting direct links (or forwarding through Layer 2 devices in the middle)

The firewall sends ICMP or ARP packets to a probe destination address to determine whether the destination address is reachable.

ip-link is associated with VGMP, the ip-link status is down, and the VGMP management group priority is lowered by default.