Solution

MS-Office is a productivity software suite developed by Microsoft that includes applications like Word, Excel, PowerPoint, and Outlook. It is not an operating system.

The other options are all examples of operating systems:

• Android: A mobile operating system developed by Google.
• Linux: An open-source operating system used in various devices, from computers to servers.
• Microsoft Windows: A popular desktop operating system developed by Microsoft.

Therefore, MS-Office is not an operating system.