Your computer is unable to access external names or IP addresses. You need to connect to external Internet resources.  What should you do first？（）

• A、In a command window， type the ipconfig /displaydns command.
• B、In the Network and Sharing Center window， click the View Full Map link.
• C、In the Network and Sharing Center window， click the Diagnose and repair link.
• D、Configure the DNS server by using an IP address provided by your Internet Service Provider （ISP）.