单项选择题

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.