You plan to deploy a fault-tolerant virtual infrastructure based on Hyper-V. The virtual infrastructure will include a two-node Hyper-V host cluster that will contain eight virtual machines （VMs）. All of the VMs will run Windows Server 2008 R2 Standard. If one of the nodes fails， the VMs must continue to run on the other node. You need to identify the minimum number and the type of licenses required for the planned deployment. What should you identify？（）

• A、two Windows Server 2008 R2 Enterprise licenses and eight Windows Server 2008 R2 Standard licenses
• B、two Windows Server 2008 R2 Enterprise licenses and four Windows Server 2008 R2 Standard licenses
• C、four Windows Server 2008 R2 Enterprise licenses
• D、eight Windows Server 2008 R2 Standard licenses