You want to configure your Windows 2000 Professional computer to remotely access your company’s Windows 2000 routing and remote access server. You configure a VPN connection. For security purposes， you configure the VPN connection to use MS-CHAP v2 only and to require encryption. You also configure TCP/IP to obtain an IP address automatically， to enable IPSec， and to set IPSec to secure server. When you try to connect， you receive the following error message， “The encryption attempt failed because no valid certificate was found.” What should you do to connect to the server？ （）

A. Enable the VPN connection to use MS-CHA
B. Change the data encryption setting to Optional Encryption.
C. Specify a TCP/IP address in the network properties.
D. Change the IPSec policy setting to Client.