your company has servers that run windows server 2008. All client computers run windows XP service pack 2 (SP2.). windows 2000 professional, or windows vista. You need to ensure all computers can use the IPv6 protocol. What should you do?（）

• A、Install service pack 4 on all windows 2000 professional computers.
• B、Upgrade the windows 2000 professional computers to windows XP SP2.
• C、Run the IPv6.exe tool on the windows 2000 professional and windows XP computers.
• D、Install active directory client extenticon. (DSClient.exe) on the windows 2000 professional and windows XP computers.