You are the administrator for a large organization with multiple remote sites.
Your supervisor would like to have remote users log in locally to their own site, but he is
nervous about security.
What type of server can you implement to ease their concerns?

A.
Domain controller

B.
Global Catalog

C.
Read-only domain controller

D.
Universal Group Membership Caching Server

Explanation:
http://technet.microsoft.com/en-us/library/cc772234%28v=ws.10%29.aspx
Read-Only Domain Controllers Step-by-Step Guide
An RODC makes it possible for organizations to easily deploy a domain controller in
scenarios where physical security cannot be guaranteed, such as branch office locations, or
in scenarios where local storage of all domain passwords is considered a primary threat,
such as in an extranet or in an application-facing role.