You have an Exchange Server 2010 organization that contains 20 Mailbox servers.You plan to create 10 mailbox databases on each Mailbox server. You need to create a naming convention for all mailbox databases.  What should you include in your naming convention（）？ 

• A、For each mailbox database， provide a database name that is unique within the organization.
• B、For each mailbox database， provide a database name that is unique within the Mailbox server.
• C、For each mailbox database file， provide a file name that is unique within the organization.
• D、For each mailbox database file， provide a file name that is unique within the Mailbox server.