A company named Contoso Ltd. has three offices. Each office is configured as an Active Directory site and contains multiple Exchange servers. Each office has a team of network support technicians. You are designing an Exchange organization for Contoso. All servers in the organization will have Exchange Server 2010 Service Pack 1 (SP1) installed. You need to implement a security solution to ensure that the team of network support technicians can manage the Exchange servers in its respective office only.

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

A.
one custom scope and one management role group

B.
one management role and three Active Directory security groups

C.
three custom scopes and three management role groups

D.
three custom scopes, three management roles, and three Active Directory security groups