You configure a Windows Server 2008 R2 Hyper-V server with several virtual machines （VMs）. A software vendor releases a software update for an application that runs on only one of the VMs. You need to plan a strategy that enables you to install and test the update without interrupting application availability and without corrupting data. What should you do first？（）

• A、Create a snapshot of the affected VM
• B、Enable the Windows Volume Snapshot Service on the Hyper-V server
• C、Export the VM
• D、Enable the Windows Volume Snapshot Service on the affected VM