A company named Contoso, Ltd. has offices in Montreal, Seattle, and Denver. An Active Directory site exists for each office. Only the Montreal site is connected to the Internet. You are designing an Exchange organization for Contoso. All servers in the organization will have Exchange Server 2010 Service Pack 1 (SP1) installed. Each office will contain two Exchange servers that each has the Mailbox, Hub Transport, and Client Access server roles installed.
You need to recommend a deployment solution for the Client Access servers.

Which of the following solutions is the best recommendation? (More than one answer choice may achieve the goal. Select the BEST answer.)

A.
one Client Access server array in each office

B.
round-robin DNS in each office a load balancing solution in each office round-robin DNS in the Montreal office

C.
one Client Access server array in each office a load balancing solution in each office

D.
one Client Access server array that contains all of the Client Access servers a load balancing solution in the Montreal office