You are an enterprise application developer. You create a Web application to call the Web services of different trucking companies. The application retrieves transit times for different routes. You create Web service proxy classes by using the Wsdl.exe utility. You need to call different Web services concurrently. You also need to ensure that the application can continue performing other tasks while the Web services are being called. You need to achieve this by using the least amount of code possible. What should you do?

A.
Use the Thread class.

B.
Use the AsyncCallback class and the IAsyncResult interface.

C.
Use the Application.DoEvents method.

D.
Use the ThreadPool class.