You have an Exchange Server 2013 organization.
A member of the legal department reports that Information Rights Management (IRM)-protected messages are
included in the results when performing an In-Place eDiscovery search.
You need to ensure that the IRM-protected messages are excluded from the results.
What should you do?

A.
From the Exchange Admin Center, modify the permissions of the discovery mailbox.

B.
From Windows PowerShell, run the Set-MailboxSearch cmdlet.

C.
From the Exchange Admin Center, run the In-Place eDiscovery & Hold wizard.

D.
From Windows PowerShell, run the Set-IRMConfiguration cmdlet.

Explanation:
See Note below.
Use the Shell to configure IRM for Exchange Search
This example configures IRM to allow Exchange Search to index IRM-protected messages.
Set-IRMConfiguration -SearchEnabled $true
Note: By default, the SearchEnabled parameter is set to $true. To disable indexing of IRM- protected
messages, set it to $false. Disabling indexing of IRM-protected messages prevents them from being returned in
search results when users search their mailbox or when discovery managers use In-Place eDiscovery.
Configure IRM for Exchange Search and In-Place eDiscovery
https://technet.microsoft.com/en-us/library/gg588319(v=exchg.150).aspx