You have two servers named FC1 and FC2 that run Windows Server 2008 R2 Enterprise.
Both servers have the Failover Clustering feature installed.
You configure the servers as a two-node cluster.
The cluster runs an application named APP1.
Business hours for your company are 09:00 to 17:00. APP1 must be available during these hours.
You configure FC1 as the preferred owner for APP1.
You need to prevent failback of the cluster during business hours.
What should you do?

A.
Set the Period option to 8 hours in the Failover properties.

B.
Set the Allow failback option to allow failback between 17 and 9 hours in the Failover properties.

C.
Enable the Prevent failback option in the Failover properties.

D.
Enable the If resource fails, attempt restart on current node policy for all APP1 resources. Set the Maximum restarts for specified period to 0.

Explanation:
Failback timing
You can set a group to fail back to its preferred node as soon as the Cluster service detects that the failed node has been restored, or you can instruct the Cluster service to wait until a specified hour of the day, such as after peak business hours.
Important
* Failback only occurs when you have defined a preferred nodes list for a resource group and failback is allowed for that resource group.
If you specify that a group failback to a preferred node and then restart the node to test the failback policy you set, the resource group will not failback. A resource group will not failback when a node is restarted after a planned shutdown and restart. To test the failback policy, you must press the reset button on the node.
Source: http://technet.microsoft.com/en-us/library/cc737785.aspx