Your network contains an Active Directory forest named contoso.com. The forest contains a child domain
named corp.contoso.com.
The network has Microsoft Exchange Server 2010 deployed.
You need to create a mail-enabled distribution group.
Which type of group should you create?

A.
Global

B.
Local

C.
Domain local

D.
Universal

Explanation:
Universal groups Groups that are used to grant permissions on a wide scale throughout a domain tree or forest.
Members of global groups include accounts and groups from any domain in the domain tree or forest.
Microsoft Exchange Server 2007: Implementation and Administration. By Jim McBee, Benjamin Craig page
248: Only universal groups should be used as mail-enabled groups.