उत्तर : 3. "Ctrl + L"
व्याख्या :

Most people know that CTRL + N will create a new workbook in Excel. However, there are many different ways to close workbooks. Both CTRL + W and CTRL + F4 will close the current workbook. If you would like to close all workbooks that are open, as well as Excel itself, the shortcut that will achieve this is Alt + F4.