When a new SIP phone is registered to Cisco Unified Communications Manager, it keeps failing and showing an `unprovisioned` error message in the phone display. ...

When a new SIP phone is registered to Cisco Unified Communications Manager, it keeps failing and showing an `unprovisioned` error message in the phone display. Which problem is a possible cause of this issue?

A. Auto-registration is disabled on the Cisco Unified Communications Manager nodes and the phone device does not have a DN configured. B. The DN assigned to the phone is already in use by another SIP phone. C. The phone cannot download and install the latest firmware. D. The DHCP settings are set incorrectly and the phone does not have an alternate TFTP defined. E. The DN configuration for this phone is shared with an SCCP phone, which is not supported.