问题：

[单选]

Your company has a main office and a branch office. The offices connect by using WAN links. The network consists of a single Active Directory domain. An Active Directory site exists for each office.  
Servers in both offices run Windows Server 2008 R2 Enterprise.  
You plan to deploy a failover cluster solution to service users in both offices. 
You need to plan a failover cluster to meet the following requirements：
èMaintain the availability of services if a single server fails
èMinimize the number of servers required
What should you include in your plan？（）

A . Deploy a failover cluster that contains one node in each office.
B . Deploy a failover cluster that contains two nodes in each office.
C . In the main office， deploy a failover cluster that contains one node. In the branch office， deploy a  failover cluster that contains one node.
D . In the main office， deploy a failover cluster that contains two nodes. In the branch office， deploy a  failover cluster that contains two nodes.