How is the region assigned to a device such as an IP phone?

A.	Regions are assigned directly in the device configuration page.
B.	Regions can be assigned only through a device pool.
C.	Regions can be assigned either directly on the device configuration page or through the device pool. If both configurations exist, the device pool region configuration takes precedence.
D.	Regions can be assigned either directly on the device configuration page or through the device pool. If both configurations exist, the device region configuration takes precedence.