You connect an external monitor to a portable computer. You need to increase the available desktop area to include the external monitor. What should you do?（） 

• A、From the Display properties, extend the display. 
• B、From the Display properties, modify the resolution settings.
• C、Restart the computer in VGA Mode. Run dxdiag.exe. 
• D、Restart the computer in VGA Mode. Install the most up-to-date driver for the video graphics adapter.