This question asks to identify the option that does not represent a standard or valid method for saving a workbook in Microsoft Excel.

Understanding Microsoft Excel Saving Methods

Microsoft Excel provides several ways for users to save their work, ensuring that data is preserved. Let's examine the common methods:

• Pressing 'Ctrl + S': This is a universal keyboard shortcut across many applications, including Excel, used to quickly save the current workbook. If the workbook has been saved before, it updates the existing file. If it's a new workbook, it usually prompts the 'Save As' dialog box.
• Clicking 'File' → 'Save': This command performs the same function as the 'Ctrl + S' shortcut. It saves the current workbook, updating the existing file if it has been previously saved, or opening the 'Save As' dialog for new workbooks.
• Selecting 'File' → 'Save As': This option allows the user to save the workbook with a different name, in a different location, or in a different file format. It's used for creating copies or versions of the workbook.

Analyzing the 'Close' Functionality

Now let's consider the option that is presented as NOT a saving method:

• Using 'File' → 'Close': The primary function of the 'File' → 'Close' command in Excel is to close the currently active workbook window. It is not inherently a saving command. However, if the workbook contains unsaved changes when the 'Close' command is initiated, Excel will typically prompt the user with a dialog box asking whether they want to save the changes before closing. While this prompt *offers* the chance to save, the 'Close' action itself is not a direct method *of saving*. The saving happens as a consequence of responding to the prompt, not as the action of closing itself. Therefore, it's not considered a primary or direct way to save a workbook compared to the other options.

Comparing these actions, 'Ctrl + S', 'File → Save', and 'File → Save As' are all direct commands whose main purpose is to save the workbook's data. 'File → Close', conversely, is primarily for closing the workbook.

Thus, using 'File' → 'Close' is NOT a valid way to save a workbook in the direct sense.