You have a Windows Server 2008 R2 Hyper-V server. Virtual machines （VMs） store data on pass- through disks. You need to design a backup solution that allows you to restore VMs. What should you do？（）

• A、Back up the VMs by using Windows Server Backup within the VMs
• B、Create checkpoints of the VMs by using Microsoft System Center Virtual Machine Manager （VMM） 2008 R2
• C、Back up the system state on the VMs by using Windows Server Backup within the VMs
• D、Back up the Hyper-V server by using Microsoft System Center Data Protection Manager （DPM） 2007 with SP1