Your network has a Lync Server 2010 infrastructure that contains the following servers:
* One Mediation Server
* Two Directors in a Director pool
* Two Edge Servers in an Edge pool
* Two Enterprise Edition servers in a Front End pool
You plan to create a disaster recovery site. You need to recommend which servers are required for the disaster recover site to ensure that IM and Presence information is available if the main site is unavailable. The solution must ensure that remote users can access the disaster recovery site. Which two roles should you include in the recommendation? (Each correct answer presents part of the solution. Choose two.)

A.
Director

B.
Mediation Server

C.
Front End Server

D.
Edge Server

Explanation:
IM and Presence functionality is handled by Front End Servers. Remote users connectivity is handled by Edge Servers (http://technet.microsoft.com/en-us/library/gg412956.aspx, http://technet.microsoft.com/en-us/library/gg398775.aspx)