After properly configuring multiple VLANs, an administrator has decided to secure its VLAN network. Which three steps are required to secure this environment? (Choose three.)

A.
If a port is connected to a foreign device make sure to disable CDP, DTP, RPR, PAgP, UDLP, and any other unnecessary protocols, and enable UplinkFast/BPDU guard on it.

B.
Enable root guard feature to prevent a directly or indirectly connected STP-capable device from affecting the location of the root bridge.

C.
Configure VTP domains appropriately or turn off VTP altogether to limit or prevent possible undesirable protocol interaction with regards to the network-wide VLAN configuration.

D.
Set the native VLAN ID to match the port VLAN ID of any 802.1q trunk to prevent spoofing.

E.
Disable all unused ports and place them in an unused VLAN to avoid unauthorized access.