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.