You have an Exchange organization that contains Exchange 2000 Server Service Pack 3 (SP3), Exchange Server 2003 Service Pack 2 (SP2), and Exchange Server 2007 Service Pack 1 (SP1) servers. You need to transition the organization to Exchange Server 2010. What should you do first?()
A. Remove all Exchange Server 2007 SP1 servers from the organization.
B. Remove all Exchange 2000 Server and all Exchange Server 2003 servers from the organization.
C. Remove all Exchange 2000 Server servers from the organization,and then upgrade all Exchange Server 2007 servers to SP2.
D. Remove all Exchange Server 2003 servers from the organization,and then upgrade all Exchange Server 2007 servers to SP2.