What are Cisco CallManager Regions used for?

A.
Specify the bandwidth used for audio and video calls.

B.
Define the time zones for devices connected to the Cisco CallManager.

C.
Provide alternate call routing when the primary call path is unavailable.

D.
Implement call admission control in a centralized call processing deployment.

E.
Assign directory numbers to devices as they connect to the IP telephony network.