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.