You are the messaging engineer for your company. You plan to deploy Exchange Server 2007. You need to evaluate the elements of your Active Directory infrastructure that will influence how you design your messaging environment. Which three elements should you evaluate? (Each correct answer presents part of the solution. Choose three.)

A.
The number of organizational units in each Active Directory domain

B.
The number of Active Directory forests

C.
The NetBIOS domain name of the forest root domain

D.
The number of global catalog servers for each site

E.
The design of Active Directory sites and subnets

F.
The placement of domain naming master role

Explanation:
http://www.msexchange.org/tutorials/Installing-Exchange-2007-Part1.html