You have an Exchange Server 2010 organization.  You need to recommend a solution that prevents the permanent deletion of e-mail messages from themailboxes of employee who have been dismissed from the company.  What should you recommend？（）

• A、Implement managed folders.
• B、Implement a legal hold for each mailbox.
• C、Implement a Retention Policy for each mailbox.
• D、Implement an Outlook Protection Rule for each mailbox.