You work as the enterprise exchange administrator at TestKing.com. TestKing.com makes use of Microsoft Exchange Server messaging solution. TestKing.com has its headquarters in Chicago and branchoffices in Dallas and Miami. There is an Active Directory for every office namely：* Chicago office - SiteC* Dallas office - SiteD* Miami office - SiteM You are in the process of deploying Exchange Server 2010 servers in SiteC. In the near future you plan todeploy Exchange Server 2010 in SiteD as well as SiteM. During the course of the day you receive aninstruction from the CIO to propose a solution that will connect the Exchange Server 2010 servers to theExchange Server 2003 servers whilst ensuring that： * The e-mail messages that come from the Exchange Server 2010 server mailboxes to the ExchangeServer 2003 server mailboxes should come from a server in SiteD. * The e-mail messages that come from the Exchange Server 2010 server mailboxes to the ExchangeServer 2003 server mailboxes should come from a server in SiteC. What should you do？（）

A. Test best option would be to set up an X400 connector to SiteC as well as changing the cost value for the original routing group connector.
B. Test best option would be to set up a new routing group connector as well as changing the default routing group connector.
C. Test best option would be to combine the Exchange Server 2003 servers and Exchange Server 2010 servers into one routing group.
D. Test best option would be to set up one Active Directory SMTP site link as well as two SMTP connections.