You deploy a server that runs Microsoft Exchange Server 2003 Service Pack  2. You also deploy mobile devices that run Microsoft Windows Mobile 5.0 with the Microsoft Messaging and Security Feature Pack.   You need to ensure that the Windows Mobilebased devices are as secure as possible from brute force password attacks.   What should you do？（）

• A、Set the Microsoft ActiveSync synchronization schedule on the mobile devices to five-minute intervals.
• B、Enable the Wipe devices after failed attempts option and specify a valid value for the option.
• C、Configure the Default Domain Group Policy object to enable Password complexity.
• D、Configure the Default Domain Group Policy object to specify a valid value for the Account Lockout Threshold.