Your environment includes the virtual machines （VMs） shown in the following table.  server Server1 and Server2 communicate with each other over a Hyper-V private virtual network. End-user connectivity to the application server is provided by an external virtual network. You need to monitor network traffic between Server1 and Server2 so that you can create a baseline to appropriately set thresholds for future monitoring. Which counter should you monitor？（）

• A、Network Interface Bytes Total/sec
• B、Hyper-V Virtual Switch Bytes/sec
• C、Hyper-V Virtual Network Adapter Bytes Sent/sec
• D、Hyper-V Virtual Network Adapter Bytes Received/sec