You work as the enterprise exchange administrator at TestKing.com. TestKing.com makes use of Microsoft Exchange Server messaging solution. The TestKing.com network consists of a single ActiveDirectory domain named testking.com. The TestKing.com network contains the following： * Exchange 2000 Server Service Pack 3 （SP3） servers. * Exchange Server 2003 Service Pack 2 （SP2） servers. * Exchange Server 2007 Service Pack 1 （SP1） servers. You need to install Exchange Server 2010 to the TestKing.com network； however， you need to changes tothe existing servers for the installation of the Exchange Server 2010 servers. What should you do？（）

• A、You should consider removing all Exchange 2000 Server servers.Thereafter all Exchange Server 2007 servers should be upgraded to SP2.
• B、You should consider removing all Exchange Server 2007 SP1 servers.
• C、You should consider removing all Exchange Server 2003 servers.Thereafter all Exchange Server 2007 servers should be upgraded to SP2.
• D、You should consider removing all Exchange 2000 Server as well as all Exchange Server 2003 servers.