Your network contains an Active Directory domain.
You need to restore a deleted computer account from theActive Directory Recycle Bin.
What should you do?

A.
From the command prompt, run recover.exe.

B.
From the command prompt, run ntdsutil.exe.

C.
From the Active Directory Module for Windows PowerShell, run the Restore-Computer cmdlet.

D.
From the Active Directory Module for Windows PowerShell, run the Restore-ADObject cmdlet.

Explanation:
http://technet.microsoft.com/en-us/library/dd379509%28v=ws.10%29.aspx
Step 2: Restore a Deleted Active Directory Object
Applies To: Windows Server 2008 R2
This step provides instructions for completing the following tasks with Active Directory Recycle Bin:
Displaying the Deleted Objects container
Restoring a deleted Active Directory object using Ldp.exe
Restoring a deleted Active Directory object using the Get-ADObject and Restore-ADObject cmdlets
Restoring multiple, deleted Active Directory objects
…
To restore a single, deleted Active Directory object using the Get-ADObject and Restore-ADObject cmdlets
1. Click Start, click Administrative Tools, right-click Active Directory Module for Windows PowerShell, and
then click Run as administrator.
2. At the Active Directory module for Windows PowerShell command prompt, type the following command,
and then press ENTER:
Get-ADObject -Filter {String} -IncludeDeletedObjects | Restore-ADObject
For example, if you want to restore an accidentally deleted user object with the display name Mary, type the
following command, and then press ENTER:
Get-ADObject -Filter {displayName -eq “Mary”} -IncludeDeletedObjects | Restore-ADObject
http://blogs.msdn.com/b/dsadsi/archive/2009/08/26/restoring-object-from-the-active-directory-recycle-bin-usingad-powershell.aspx
Restoring object from the Active Directory Recycle Bin using AD Powershell