All the options (given in the question) are examples of Microsoft operating systems. MS-DOS: short for Microsoft Disk Operating System was the main operating system for IBM PC compatible personal computers during the 1980s to the mid-1990s: Windows 98: code- named Memphis, is a graphical operating system by Microsoft; Windows 95: a consumer-oriented operating systemof Microsoft; Windows 2000: an operating system for use on both client and server computers, succeeded Windows NT 4.0: Windows 3.1: codenamed Janus, is a series of 16-bit operating systems produced by Microsoft for use on personal computers, was superseded by Windows 95.