Which four methods can be used to protect IP phones? (Choose four.)

A.
Use a firewall with the Cisco Unified Communications Manager cluster to prevent attacks from inside and outside the organization.

B.
Dedicate a TFTP server for each voice network segment.

C.
Prevent/Restrict/Disable GARP.

D.
Disable the Settings button.

E.
Disable the PC port.

F.
Use signed loads.