You are the network administrator for your company. The network consists of a single Active Directory domain. The network contains an application server running Windows Server 2003.   Users report intermittent slow performance when they access the application server throughout the day. You find out that the network interface on the application server is being heavily used during the periods of slow performance. You suspect that a single computer is causing the problem.You need to create a plan to identify the problem computer.   What should you do？（）

• A、 Monitor the performance monitor counters on the application server by using System Monitor.  
• B、 Monitor the network traffic on the application server by using Network Monitor.
• C、 Monitor network statistics on the application server by using Task Manager.
• D、 Run network diagnostics on the application server by using Network Diagnostics.