Click the Exhibit button. The resource requested by the RequestDispatcher is available and implemented by the Destination Servlet. What is the result？（）
- AAn exception is thrown at runtime by SourceServlet.
- BAn exception is thrown at runtime by DestinationServlet.
- COnly "hello from dest" appears in the response output stream.
- DBoth "hello from source" and "hello from dest" appear in the response output stream.