What is the minimum number of partitions that must he defined, given these dial plan rules?

•All employees can call local and service numbers
•Managers can call long-distance and international numbers.
•Executives can call all PSTN numbers, including premium numbers
•Only administrative assistants can call executives
•Incoming calls can only be routed to TelePresence systems, not to trunks

A.
3

B.
4

C.
5

D.
6

E.
7

F.
8