our company has a main office and 15 branch offices. The company has a single active directory domain. All servers run windows server 2008.You need to ensure that the VPN connections between the office and the branch offices meet the following requirements:All data must be encrypted by using end-to-end encryption.The vpn connection must use computer-level authentication.User names and passwords cannot be used for authentication.What should do?（）

• A、Configure an ipsec connection to use tunnel mode and preshared key authentication.
• B、Configure a PPTP connection to use version 2 of the MS-CHAP v2 authentication.
• C、Configure a L2TP/IPsec connection to use the EAP-TLS authentication.
• D、Configure a L2TP/IPsec connection to use version 2 of the MS-CHAP v2 authentication.