Your network contains an Active Directory domain. The functional level of the domain is
Windows Server 2003.
The domain contains five domain controllers that run Windows Server 2008 and five domain
controllers that run Windows Server 2008 R2.
You need to ensure that SYSVOL is replicated by using Distributed File System Replication
(DFSR).
What should you do first?

A.
Run dfsrdiag.exe PollAD.

B.
Run dfsrmig.exe /SetGlobalState 0.

C.
Upgrade all domain controllers to Windows Server 2008 R2.

D.
Raise the functional level of the domain to Windows Server 2008.

Explanation:
http://technet.microsoft.com/en-us/library/cc753479%28v=ws.10%29.aspx
Distributed File System
Distributed File System (DFS) Namespaces and DFS Replication offer simplified, highlyavailable access to files, load sharing, and WAN-friendly replication. In the Windows
Server® 2003 R2 operating system, Microsoft revised and renamed DFS Namespaces
(formerly called DFS), replaced the Distributed File System snap-in with the DFS

Management snap-in, and introduced the new DFS Replication feature. In the Windows
Server® 2008 operating system, Microsoft added the Windows Server 2008 mode of
domain-based namespaces and added a number of usability and performance
improvements.
What does Distributed File System (DFS) do?
The Distributed File System (DFS) technologies offer wide area network (WAN)-friendly
replication as well as simplified, highly-available access to geographically dispersed files.
The two technologies in DFS are the following:
DFS Namespaces. Enables you to group shared folders that are located on different servers
into one or more logically structured namespaces. Each namespace appears to users as a
single shared folder with a series of subfolders. This structure increases availability and
automatically connects users to shared folders in the same Active Directory Domain
Services site, when available, instead of routing them over WAN connections.
DFS Replication. DFS Replication is an efficient, multiple-master replication engine that you
can use to keep folders synchronized between servers across limited bandwidth network
connections. It replaces the File Replication Service (FRS) as the replication engine for DFS
Namespaces, as well as for replicating the AD DS SYSVOL folder in domains that use the
Windows Server 2008 domain functional level.