Which three Cisco Unified CallManager configuration steps are required to support third party SIP phones? (Choose three.)
A. configure the device in Cisco Unified CallManager
B. change the proxy address in the SIP phone to an IP address or the Fully Qualified Domain Name (FQDN) of Cisco Unified CallManager
C. associate the device with the end user
D. configure the phone with the TLS username and password
E. configure the end user in Cisco Unified CallManager
F. add the MAC address of the Cisco Unified CallManager server to the SIP phone configuration page
