Which one of the following is an appropriate routine to shut down a non-responding application?

• A. Close all open documents and press the power button until the computer automatically switches off.
• B. Press "Ctrl + Alt + Delete", then select the non- responding application in the Task Manager window and click "End Task".
• C. Pull out the power cable from the back of the computer.
• D. Click "Shut Down" on the on the Start menu and choose "Shut down" from the Shut Down Windows drop-down list.