You have an Exchange Server 2010 server that contains a single mailbox database.All users run Microsoft Office Outlook and Outlook Web App.You discover that users cannot restore e-mail messages from the Recover Deleted Items folder.You need to ensure that users can restore e-mail messages from the Recover Deleted Items folder.What should you do？（）

A. From the Exchange Management Console （EMC）， modify the properties of the mailbox database
B. From the Exchange Management Console （EMC）， modify the properties of the Mailbox server object
C. From the Exchange Management Shell， create a management role and then assign the role to all users
D. From the Exchange Management Shell， create a retention policy and then assign the policy to all user