You work as a network Exchange administrator at Company.com.The Company.com network currently consists of a single Active Directory forest containing a single domain named Company.com.The Company.com servers are currently configured as members of the Database Availability Group （DAG）.During the course of the business week you receive instruction from Company.com to deploy Microsoft Exchange Server 2010 by selecting the operating system which can be used to install Microsoft Exchange Server 2010 whilst ensuring your solution minimizes the cost.What should you do？（）

A. You should consider having Microsoft Exchange Server 2010 installed on Microsoft Windows Server 2003 Service Pack 2 （SP2） Enterprise Edition.
B. You should consider having Microsoft Exchange Server 2010 installed on Microsoft Windows Server 2008 Service Pack 2 （SP2） Enterprise Edition.
C. You should consider having Microsoft Exchange Server 2010 installed on Microsoft Windows Server 2003 R2 Standard Edition.
D. You should consider having Microsoft Exchange Server 2010 installed on Microsoft Windows Server 2008 R2 Standard Edition.