You are the administrator of B & G Enterprises. Your Windows 2000 Server is configured to use the NWLink IPX/SPX compatible protocol. Your network clients also use NWLink IPX/SPX protocol. Your clients complain that they are not able to connect to the Windows 2000 Server； they can however connect to each other. What is the most likely cause of the problem？ （）

• A、The SUBNET Mask was set incorrectly.
• B、File permissions were set to no access.
• C、An incorrect frame type was selected on the server.
• D、The workstation service on the Windows 2000 Server failed to start.