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？（）
- ABack up the VMs by using Windows Server Backup within the VMs
- BCreate checkpoints of the VMs by using Microsoft System Center Virtual Machine Manager （VMM） 2008 R2
- CBack up the system state on the VMs by using Windows Server Backup within the VMs
- DBack up the Hyper-V server by using Microsoft System Center Data Protection Manager （DPM） 2007 with SP1