You have an Exchange Server 2010 organization.  All users connect to their mailboxes by using Microsoft Office Outlook 2007 Service Pack 2 （SP2） andWindows 7.  Your companys security administrators deploy Outlook Protection Rules.  You need to recommend a client connection solution for the organization to ensure that Outlook ProtectionRules can be used.  What should you recommend？（）

• A、Upgrade all client computers to Outlook 2010.
• B、Instruct all users to connect to Outlook Web App （OWA）.
• C、Instruct all users to install the Rights Management Service （RMS） client.
• D、Instruct all users to install the Secure/Multipurpose Internet Mail Extensions （S/MIME） control.