All client computers on your company network run Windows XP and are members of an Active Directory Domain Services domain. You plan to migrate all computers to Windows 7. You also plan to deploy a new VPN server to support remote network access for the computers. You need to ensure that all computers will be supported for remote access during the migration to Windows 7. What should you do?（）

• A、Set the VPN server to Layer 2 Tunneling Protocol.
• B、Set the VPN server to Secure Socket Tunneling Protocol.
• C、Set the VPN server to Internet Key Exchange version 2.
• D、Configure the Direct Access feature on the VPN server.