When a Cisco Unified CallManager group has its primary, secondary, and tertiary servers changed, how are those changes propagated to the IP phones registered to the group?

When a Cisco Unified CallManager group has its primary, secondary, and tertiary servers changed, how are those changes propagated to the IP phones registered to the group?

A.
The IP phones will automatically reregister with the new primary server.

B.
The IP phones will need to be reset so that a new configuration file can be downloaded from the TFTP server.

C.
The primary Cisco Unified CallManager server automatically pushes a new configuration file to the IP phones in the affected device pool.

D.
The device pools will need to be edited so that the new Cisco Unified CallManager group information is applied to the appropriate device pools.