Your network connects to the Internet by using a server that runs Microsoft Forefront Threat Management Gateway (TMG).
The network has a Lync Server 2010 infrastructure that contains an Edge Server and a Front End Server.
All client computers run Microsoft Lync 2010. Some users work remotely.
Remote users report they are unable to expand distribution groups.
You verify that all of the users can initiate IM conversations.
You need to enable distribution group expansion for all users.
What should you do first?

A.
Install a Lync Server 2010 Director.

B.
Create a Web publishing rule on the TMG server.

C.
On the Front End Server, run abserver.exe.

D.
On the Edge Server, run the Update-CsAddressBook cmdlet.

Explanation:
http://ucmadeeasy.wordpress.com/2010/09/24/publishing-lync-server-2010-rc-simple-urls-and-web-components-with-forefront-tmg-2010/