You have an Exchange Server 2010 server named Server1.Server1 has a single mailbox database named DB1 that contains 300 mailboxes.You need to ensure that a warning message is issued when a mailbox exceeds 2 GB.The solution must use the minimum amount of administrative effort. What should you do？（）

• A、From the properties of DB1， configure options on the Limits tab.
• B、From the properties of each mailbox， modify the storage quotas.
• C、From the properties of Server1， configure options on the Messaging Records Management tab.
• D、From Managed Default Folders， modify the properties of the Entire Mailbox managed folder.