Your network contains a Virtualization environment that includes the following：
- 10 hosts that run VMware ESX Server 4.0
- Microsoft System Center Virtual Machine Manager
- 50 Hyper-V hosts that run Windows Server 2008 R2
Each Virtualization host contains a minimum of 15 virtual machines （VMs）.
You need to recommend a solution to ensure that users can create and deploy VMs to any of the virtualization hosts. The VMs must be based on templates created by an administrator.
What should you include in the recommendation？（）

Your network includes 40 servers that run Windows Server 2008 R2.
You plan to virtualize the servers by using Hyper-V in a failover cluster. Your plan must allow for up to two offline host servers while still maintaining highly available virtual machines. You need to recommend the minimum number of Hyper-V host servers for the cluster.
How many servers should you recommend？（）