Your environment includes a server that runs Windows Server 2008 R2 with the Hyper-V role installed. The server hosts several virtual machines （VMs）. When you attempt to start a VM named VM1， you  receive the following error message： The application encountered an error while attempting to change the state of ’VM1’. ’VM1’ failed to start. Microsoft Emulated IDE Controller （Instance ID  {83F8638B-8DCA-4152-9EDA-2CA8B33039B4}）： Failed to Power on with Error ’The chain of virtual hard disks is broken. The system cannot locate the parent virtual hard disk for the differencing disk.’ Failed to open virtual disk ’V ：/ VM1/VM1.vhd’. A problem was encountered opening a virtual disk in the chain of differencing disks， ’IDE/ATAPI’：  ’The system cannot find the file specified.’ Failed to open virtual disk ’V ：/ VM1/VM1.vhd’. A problem was encountered opening a virtual disk in the chain of differencing disks， ’L ：/ Base/W2K8R2EERCBASE+.vhd’： ’The system cannot find the file specified.’You need to be able to start VM1. What should you do？（）

• A、Merge the differencing disk.
• B、Compact the differencing disk.
• C、Reconnect the differencing disk.
• D、Convert the parent virtual hard disk.