The correct answer is B. 1984.
MS-DOS (Microsoft Disk Operating System) is a family of disk operating systems (OS) produced and marketed by Microsoft for personal computers. MS-DOS was the dominant personal computer operating system in the late 1980s and early 1990s, and in the early 1990s, it was estimated to be installed on over 90% of all personal computers.
MS-DOS was first released in 1981 as a 16-bit operating system for the IBM PC. It was originally developed by Tim Paterson of Seattle Computer Products (SCP) as QDOS (Quick and Dirty Operating System). Microsoft acquired QDOS in 1980 and renamed it MS-DOS.
MS-DOS was a single-user, single-tasking operating system. It provided a command-line interface for users to interact with the computer. MS-DOS also included a number of built-in utilities, such as a text editor, a file manager, and a command interpreter.
MS-DOS was a popular operating system for personal computers in the 1980s and early 1990s. It was used by a wide range of users, from home users to businesses. MS-DOS was also used as the basis for a number of other operating systems, such as Windows and OS/2.
MS-DOS was eventually replaced by Windows as the dominant personal computer operating system. However, MS-DOS remains an important part of the history of personal computing.
Option A is incorrect because MS-DOS was not developed in 1991. MS-DOS was first released in 1981.
Option C is incorrect because MS-DOS was not developed in 1971. MS-DOS was first released in 1981.
Option D is incorrect because MS-DOS was not developed in 1961. MS-DOS was first released in 1981.