You work as the enterprise exchange administrator at Xxx .Xxx is using Microsoft Exchange Server 2010 as their messaging solution. The Xxx contains an Exchange Server 2010 Mailbox server named XXX- EX02.What actions must you take to check when last employees logged on to XXX- EX02？（）

• A、You must configure real time block lists （RBLs）.
• B、You must use the Exchange Server User Monitor （ExMon）.
• C、You must use the Get-MailboxStatistics.
• D、You must use the administrator audit logging.