Your network contains a Web server named Server1 that runs Windows Server 2008 R2.
You modify the configuration of Server1.
You need to restore the previous Web server configuration.
What should you run?

A.
appcmd.exe

B.
iisback.vbs

C.
iisext.vbs

D.
iisreset.exe

Explanation:
Backup/Restore via the command line
Backing up IIS7 configuration is as simple as copying the windowssystem32inetsrvconfig directory (and subdirectories) into a backup directory, so you don’t need anything special to do it. Just include this directory in whatever your OS/content back-up plan is, or write a custom script to do it.
To help make managing backups easy, we’ve added a simple cmd-line option to AppCmd.exe that makes management of backup/restore sets easy. For example, to backup configuration, run the follow command:
%windir%system32inetsrvappcmd.exe add backup “My Backup Name”
to restore that backup, run this command:
%windir%system32inetsrvappcmd.exe restore backup “My Backup Name”
to delete a backup, run this command:
%windir%system32inetsrvappcmd.exe delete backup “My Backup Name”
http://blogs.iis.net/bills/archive/2008/03/24/how-to-backup-restore-iis7-configuration.aspx