You are the messaging engineer for your company. Your company has a single Microsoft Exchange Server 2003 server that supports mailboxes and public folders. The Exchange Server 2003 server hosts mailboxes for each conference room in your company. Each conference room mailbox holds the schedule for that particular conference room. You install a new Exchange Server 2007 server that hosts the Mailbox server role. You plan to move the conference room mailboxes from Exchange Server 2003 to Exchange Server 2007. You need to ensure that Exchange Server 2007 conference room mailboxes are configured as room resources. What should you do?

A.
Ensure that the conference room mailboxes are configured as resources of type room.

B.
Ensure that the conference room mailboxes are configured as resources of type linked.

C.
Use the Exchange Management Shell to add the text ConferenceRoom to the resource property schema.

D.
Use the Exchange Management Console to set the Custom Attributes 10 and 11 for each conference room mailbox. Enter the text resource in Custom Attribute 11. Enter the text room in Custom Attribute 12.

Explanation:
Resource mailboxes are those representing conference rooms or shared equipment. These can be included as resources in meeting requests, providing a simple and efficient way for an organization to utilize assets.

In Exchange 2003, you had to use shared mailboxes to represent resources. To take full advantage of Exchange 2007 resource mailbox features, you must convert these objects to resource mailboxes.

http://technet.microsoft.com/en-us/library/bb124374.aspx

To convert a shared mailbox to a resource mailbox, run:

Set-Mailbox ConfRoom1 -Type Room

For Type parameter you can choose values: Regular, Room, Equipment, or Shared.

http://technet.microsoft.com/en-us/library/bb201749.aspx