You network consists of a single Active Directory domain. All domain controllers run
Windows Server 2008 R2.
You need to reset the Directory Services Restore Mode (DSRM) password on a domain
controller.
What tool should you use?

A.
Active Directory Users and Computers snap-in

B.
ntdsutil

C.
Local Users and Groups snap-in

D.
dsmod

Explanation:
http://technet.microsoft.com/en-us/library/cc753343%28v=ws.10%29.aspx
Ntdsutil
Ntdsutil.exe is a command-line tool that provides management facilities for Active Directory
Domain Services (AD DS) and Active Directory Lightweight Directory Services (AD LDS).
You can use the ntdsutil commands to perform database maintenance of AD DS, manage
and control single master operations, and remove metadata left behind by domain
controllers that were removed from the network without being properly uninstalled. This tool
is intended for use by experienced administrators.
..
Commands set DSRM password – Resets the Directory Services Restore Mode (DSRM)
administrator password.
Further information:
http://technet.microsoft.com/en-us/library/cc754363%28v=ws.10%29.aspx
Set DSRM password
Resets the Directory Services Restore Mode (DSRM) password on a domain controller. At
the Reset DSRM Administrator Password: prompt, type any of the parameters listed under
“Syntax.”
This is a subcommand of Ntdsutil and Dsmgmt. Ntdsutil and Dsmgmt are command-line
tools that are built into Windows Server 2008 and Windows Server 2008 R2. Ntdsutil is
available if you have the Active Directory Domain Services (AD DS) or Active Directory
Lightweight Directory Services (AD LDS) server role installed.
Dsmgmt is available if you have the AD LDS server role installed. These tools are also
available if you install the Active Directory Domain Services Tools that are part of the
Remote Server Administration Tools (RSAT).