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. TestKing.com is configured to run in an Exchange 2010 environment. The users at TestKing.com useMicrosoft Office Outlook 2010 to access the public folders. TestKing.com has joined with another company that also uses Microsoft Office Outlook 2010. You are now busy with a sharing solution for bothcompanies. You have received instructions from the CIO to propose a sharing information strategy thatensures corss-organizaional access to user contacts as well as free/busy information. What should you do？（）

A. The best option is to implementing Microsoft Modify LifeCyle Manager （ILM） 2007.
B. The best option is to create cross forest trusts.
C. The best option is to use the Microsoft Exchange Inter-Organization Replication tool.
D. The best option is to implementing Federated Sharing.