You have an Exchange Server 2010 organization.  Your company has a relationship with another company.  The partner company has an Exchange Server 2010 organization.  You need to recommend a security solution to meet the following requirements：  .Ensure that all e-mail delivery between your servers and the partner companys servers is encrypted .Ensure that all communication between your servers and the partner companys servers is authenticated What should you include in the solution？（）

• A、Active Directory Rights Management Services （AD RMS）
• B、Domain Security
• C、Forms-based Authentication
• D、Secure/Multipurpose Internet Mail Extensions （S/MIME）