You host 16 virtual machines that are distributed evenly across an 8-node Windows Server 2008 R2 Hyper-V failover cluster. You plan to perform live migrations of the VMs to prepare for the installation of software updates on the cluster. You need to perform the maximum number of simultaneous live migrations. How many live migrations should you perform simultaneously？（）

• A、one
• B、two
• C、four
• D、eight