Your network contains an Exchange Server 2010 server.All users access their mailboxes by using only Microsoft Office Outlook 2007.You configure a policy to archive all e-mail messages located in the Entire Mailbox 365 days after they are received.You need to ensure that all members of a department named Sales can retain some e-mail messages for five years. What should you create first？（）

A. a linked mailbox
B. a managed custom folder
C. a message classification
D. an Outlook Protection Rule