What should you do?

You work as an enterprise administrator at Domain.com. The Domain.com network consists of a single Active Directory domain named Domain.com. All servers on the Domain.com network run Windows Server 2008.
Domain.com has its headquarters in Chicago and quite a few branch offices in the region. The offices at Domain.com lack suitable physical security. You need to provide the users with the directory services that are suitable in a security that is not known.
What should you do?

A.
The best option is to use Active Directory Federation Services.

B.
The best option is to use Read-only domain controllers.

C.
The best option is to use Lightweight Directory Services.

D.
The best option is to use Active Directory Rights Management Services.

Explanation:
You need to use the Active Directory Federation Services and Active Directory Rights Management Services. The reason or this is the authentication between domains and document security. You also should use the Read-only domain controllers. This will allow the accounts of the users’ authentications to be cached on the server. The Lightweight Directory Services will not all full Active Directory features are needed.
Reference : Syngress – The Real MCTS-MCITP 70-649 Prep Kit – Independent and Complete Self-Paced Solutions