A、 DHCP spoofing and SPAN cannot be used on the same port of a switch.

B、 To prevent a DHCP spoofing， the DHCP server must create a static ARP entry that cannot be  updated by a dynamic ARP packet.

C、 To prevent a DHCP spoofing， the switch must have DHCP server services disabled and a static  entry pointing towards the DHCP server.

D、 DHCP spoofing can be prevented by placing all unused ports in an unused VLAN.

E、 None of the other alternatives apply.