Which quorum model should you select?

Your network contains two servers that run Windows Server 2008 R2. The servers are located on different IP subnets.
You plan to configure the servers in a twonode failover cluster. You need to select the quorum model for the cluster. The solution must ensure that users can access the cluster resources if a single node fails.
Which quorum model should you select?

A.
No Majority: Disk Only

B.
Node and Disk Majority

C.
Node and File Share Majority

D.
Node Majority

Explanation:
Quorum configuration choices
You can choose from among four possible quorum configurations:
Node Majority (recommended for clusters with an odd number of nodes)
Can sustain failures of half the nodes (rounding up) minus one. For example, a seven node cluster can sustain three node failures.
Node and Disk Majority (recommended for clusters with an even number of nodes)
Can sustain failures of half the nodes (rounding up) if the disk witness remains online. For example, a six node cluster in which the disk witness is online could sustain three node failures.
Can sustain failures of half the nodes (rounding up) minus one if the disk witness goes offline or fails. For example, a six node cluster with a failed disk witness could sustain two (3-1=2) node failures.
Node and File Share Majority (for clusters with special configurations)
Works in a similar way to Node and Disk Majority, but instead of a disk witness, this cluster uses a file share witness.
Note that if you use Node and File Share Majority, at least one of the available cluster nodes must contain a current copy of the cluster configuration before you can start the cluster. Otherwise, you must force the starting of the cluster through a particular node. For more information, see “Additional considerations” in Start or Stop the Cluster Service on a Cluster Node.
No Majority: Disk Only (not recommended)
Can sustain failures of all nodes except one (if the disk is online). However, this configuration is not recommended because the disk might be a single point of failure.
Illustrations of quorum configurations
The following illustrations show how three of the quorum configurations work. A fourth configuration is described in words, because it is similar to the Node and Disk Majority configuration illustration.
Note:
In the illustrations, for all configurations other than Disk Only, notice whether a majority of the relevant elements are in communication (regardless of the number of elements). When they are, the cluster continues to function. When they are not, the cluster stops functioning.
As shown in the preceding illustration, in a cluster with the Node Majority configuration, only nodes are counted when calculating a majority.
As shown in the preceding illustration, in a cluster with the Node and Disk Majority configuration, the nodes and the disk witness are counted when calculating a majority.
Node and File Share Majority Quorum Configuration
In a cluster with the Node and File Share Majority configuration, the nodes and the file share witness are counted when calculating a majority. This is similar to the Node and Disk Majority quorum configuration shown in the previous illustration, except that the witness is a file share that all nodes in the cluster can access instead of a disk in cluster storage.
In a cluster with the Disk Only configuration, the number of nodes does not affect how quorum is achieved. The disk is the quorum. However, if communication with the disk is lost, the cluster becomes unavailable.
Source: http://technet.microsoft.com/en-us/library/cc731739.aspx