You have an Exchange organization. The Exchange servers in the organization are configured as shown in the following table.You deploy a new Exchange Server 2010 Client Access server named Server4 and successfully update the required DNS records for Server4. You need to ensure that all users on Server3 can successfully access their mailboxes by using Exchange ActiveSync.  What should you do（）？ 

• A、On Server1， set the authentication type for the Microsoft-Server-ActiveSync virtual directory to nTLm.
• B、On Server1， set the authentication type for the Microsoft-Server-ActiveSync virtual directory to anonymous.
• C、From the Exchange Management Shell on Server4， run New-ActiveSyncDeviceAccessRule queryString * -Characteristic DeviceModel AccessLevel Allow.
• D、From the Exchange Management Shell on Server3， run Set-ActiveSyncVirtualDirectory -Identity "server3/ Microsoft-Server-ActiveSync （default web site）" -Basicauthentication：$true.