To test whether mobility control packets can reach between WLC peers in a mobility group (used to validate the anchor controller DMZ setup), two steps are required. First, the mping (mobility ping) command (Option A) is the Cisco WLC CLI tool specifically designed to test mobility control path connectivity between WLC peers. Running mping on both WLCs verifies that mobility control messages (UDP port 16666) can be exchanged bidirectionally. Second, UDP port 16666 must be open between the WLCs (Option C) --- mping uses this port, and if it is blocked by a firewall (which is common when the anchor is in a DMZ), the mobility control path cannot be established. These two steps together --- sending mping packets and confirming the firewall permits UDP 16666 --- validate mobility control plane connectivity. The eping (EoIP ping) command (Option B) tests the data path tunnel, not the control path. IP Protocol 97 (Option D) is for the data plane in legacy mobility mode. Tracert (Option E) traces routing paths but does not validate mobility protocol connectivity. Reference: WLSD Study Guide --- Mobility Group Troubleshooting, mping Command, UDP 16666 Firewall Requirements.