Your company has a domain controller that runs Windows Server 2008.
The domain controller has the backup features installed.
You need to perform a non-authoritative restore of the doman controller using an existing backup file.
What should you do?

A.
Restart the domain controller in Directory Services Restore Mode and use wbadmin to restore critical
volume

B.
Restart the domain controller in Directory Services Restore Mode and use the backup snap-in to restore
critical volume

C.
Restart the domain controller in Safe Mode and use wbadmin to restore critical volume

D.
Restart the domain controller in Safe Mode and use the backup snap-in to restore critical volume

Explanation:
almost identical to B42
http://technet.microsoft.com/en-us/library/cc816627%28v=ws.10%29.aspx
Performing Nonauthoritative Restore of Active Directory Domain Services
A nonauthoritative restore is the method for restoring Active Directory Domain Services (AD DS) from asystem
state, critical-volumes, or full server backup. A nonauthoritative restore returns the domain controller to its state
at the time of backup and then allows normal replication to overwrite that state with any changes thatoccurred
after the backup was taken. After you restore AD DSfrom backup, the domain controller queries its replication
partners. Replication partners use the standard replication protocols to update AD DS and associated
information, including the SYSVOL shared folder, onthe restored domain controller.
You can use a nonauthoritative restore to restore the directory service on a domain controller without
reintroducing or changing objects that have been modified since the backup. The most common use of a
nonauthoritative restore is to reinstate a domain controller, often after catastrophic or debilitatinghardware
failures. In the case of data corruption, do not use nonauthoritative restore unless you have confirmed that the
problem is with AD DS.
Nonauthoritative Restore Requirements
You can perform a nonauthoritative restore from backup on a Windows Server 2008 system that is a standalone server, member server, or domain controller.
On domain controllersthat are running Windows Server 2008, you can stopand restart AD DS as a service.
Therefore,in Windows Server 2008, performing offline defragmentation and other database
management tasks does not require restarting the domain controller in Directory Services Restore
Mode (DSRM). However, you cannot perform a nonauthoritative restore after simply stopping the AD
DS service in regular startup mode. You must be able to start the domain controller in Directory
Services Restore Mode (DSRM). If the domain controller cannot be started in DSRM, you must first
reinstall the operating system.
To perform a nonauthoritative restore, you need oneof the following types of backup for your backup source:
System state backup: Use this type of backup to restore AD DS. If you have reinstalled the operating
system, you must use a critical-volumes or full server backup. If you are restoring a system state backup,
use the wbadmin start systemstaterecovery command.
Critical-volumes backup: A critical-volumes backup includes all data on all volumes that contain operating
system and registry files, boot files, SYSVOL files, or Active Directory files. Use this type of backup if you
want to restore more than the system state. To restore a critical-volumes backup, use the wbadminstart
recovery command.
Full server backup: Use this type of backup only ifyou cannot start the server or you do not have a system
state or critical-volumes backup. A full server backup is generally larger than a critical-volumes backup.
Restoring a full server backup not only rolls back data in AD DS to the time of backup, but it also rolls back
all data in all other volumes. Rolling back this additional data is not necessary to achieve nonauthoritative
restore of AD DS.