You have an Exchange organization that contains Exchange 2000 Server and Exchange
Server 2003 Service Pack 2 (SP2) servers.
You plan to transition the organization to Exchange Server 2010.
You need to prepare the Exchange organization for the deployment of Exchange Server
2010 Mailbox, Client Access, and Hub Transport servers.
What should you do first?

A.
Install the Active Directory Connector (ADC).

B.
Delete all Recipient Update Service (RUS) objects

C.
Deploy an Exchange Server 2010 Edge Transport server.

D.
Remove all Exchange 2000 Servers from the organization.

Explanation:
Ex 2000 is not supported in an Exchange 2010 organization.
http://technet.microsoft.com/en-us/library/aa998604.aspx