问题：

[单选]

Your network consists of a single Active Directory domain. All domain controllers run Windows Server2008 R2. Your company and an external partner plan to collaborate on a project. The external partner has an Active Directory domain that contains Windows Server 2008 R2 domain controllers.
You need to design a collaboration solution that meets the following requirements：  
èAllows users to prevent sensitive documents from being forwarded to untrusted recipients or from being  printed.  
èAllows users in the external partner organization to access the protected content to which they have been granted rights.  
èSends all inter-organizational traffic over port 443.  
èMinimizes the administrative effort required to manage the external users.
What should you include in your design？（）

A . Establish a federated trust between your company and the external partner. Deploy a Windows Server 2008 R2 server that has Microsoft SharePoint Foundation 2010 installed.
B . Establish a federated trust between your company and the external partner. Deploy a Windows Server 2008 R2 server that runs Microsoft SharePoint 2010 and that has the Active Directory Rights  Management Services （AD？RMS） role installed.
C . Establish an external forest trust between your company and the external partner. Deploy a Windows Server 2008 R2 server that has the Active Directory Certificate Services server role installed. Implement Encrypting File System （EFS）.
D . Establish an external forest trust between your company and the external partner. Deploy a Windows Server 2008 R2 server that has the Active Directory Rights Management Service （AD？RMS）role installed  and Microsoft SharePoint Foundation 2010 installed.