问题：

[单选]

You are the network administrator for one of your company's branch offices. Ten employees work in the branch office. All client computers in the branch office run Windows XP Professional. All client computers have manually configured IP addresses in the 192. 168. 1. 0/24 range. The branch office has a cable modem connection to the Internet. All employees in the branch office need access to the main office by means of a virtual private network (VPN) connection over the Internet. The VPN connection is configured as shown in the exhibit.

Employees in the branch office report that they cannot access resources that are located on the main office network. You investigate and discover that you can establish a VPN connection locally on a client computer named Pro1 and can access main office network resources. However, you cannot connect to Pro1 from other computers on the branch office network. You want all employees in the branch office to be able to access main office network resources by means of the VPN connection on Pro1.
What should you do?（）

A . Disable Windows Firewall on the main office VPN connection. 
B . Add a port exception to Windows Firewall to allow incoming PPTP traffic on the main office VPN connection.
C . Select the Allow other network users to control or disable the shared Internet connection check box.
D . Configure all client computers in the branch office to obtain IP addresses automatically.