What is the recommended way to configure redundant Cisco Unified Communications Manager
subscribers for Cisco IP phone registration in a single cluster for the Cisco Unified Contact Center
Enterprise solution?

A.
add a redundant device pool to the Cisco Unified CallManager Group configuration

B.
add a second TFTP server to the cluster

C.
add an additional Cisco Unified Communications Manager subscriber to the Cisco Unified
Communications Manager Group defined in Device pool of the Cisco IP Phone

D.
use an SRST reference in the device pool