While replacing a Cisco IP phone, the technician notices that the phone is not functional The phone is receiving power from a Cisco Catalyst PoE switch, and the phone backup software image is loaded but the phone still fails to complete the bootup To recover the phone what is the next approach?
A. verify the IP phone settings on the Cisco Unified CM
B. contact a Cisco TAC engineer
C. perform the factory reset on the IP phone
D. connect the IP phone to a different VLAN on another Cisco Catalyst switch
