Which is NOT a software in following list?

Concept

Software is a set of programs or instructions that tell a computer what to do. A software item — an application, a utility, or an operating system — is a different kind of thing from a company, which is a business that develops and sells such products. To answer a "which is NOT a software" question, find the single entry that names a producer or vendor rather than a program.

Application

Classify each entry in the list as either a kind of software or an organisation:

• OpenOffice — an open-source office productivity suite (word processor, spreadsheet, and so on): this is software.

• DOS — Disk Operating System, an early operating system that manages a computer's hardware and files: this is system software.

• Antivirus — a utility program that detects and removes malware: this is software.

• Microsoft — a corporation (Microsoft Corporation) that develops and sells products such as Windows and Office: this is a company, not a program.

Cross-check

Three of the four entries are programs you can install and run; only "Microsoft" is the name of the business that makes software rather than a piece of software itself. Contrast it with "Microsoft Office" or "Microsoft Windows", which WOULD be software — but the bare company name is not. So the entry that is NOT a software is Microsoft.