You have an Exchange organization.All servers in the organization have Exchange Server 2010 Service Pack 1 （SP1） installed. You need to ensure that you can restore a mailbox deleted from a mailbox database if the mailbox was deleted up to six months earlier.Th solution must not require a database backup. What should you do？（）

A. Create a managed custom folder and managed content settings.
B. From the Exchange Management Shell， run the New-MailboxExportRequest cmdlet.
C. From the Exchange Management Shell， run Set-MailboxDatabase -DumpsterStatistics $true.
D. From the Exchange Management Shell， run the Export-Mailbox cmdlet.
E. Create a retention policy and a retention tag.
From the properties of the mailbox database， modify the Deletion Settings.