In the centralized call processing model, what is a disadvantage of using the traditional approach for building classes of service (as compared to the line/device approach)?

A.
The minimum number of partitions = (number of classes of service) + (number of sites) + (1 partition for all IP phone DNs)

B.
The maximum number of calling search spaces = (number of classes of service) + (number of sites)

C.
The minimum number of partitions = (number of classes of service) * (number of sites) + (1 partition for all IP phone DNs)

D.
The maximum number of calling search spaces = (number of classes of service) * (number of sites)