Refer to the exhibit.
The exhibit shows configurations for interface 5 and VLAN 20. Note that DHCP snooping and ARP protection are also enabled.
A network administrator finds that interface 5 on an AOS-Switch is disabled. The administrator re-enables the interface, but it shuts down again. What should the administrator investigate?
A. a device that sends too much unicast traffic
B. rogue DHCP server
C. a loop on the interface
D. a device that sends unauthorized ARP messages