Which was the last version of MSDOS that was released separately?

MS-DOS 6.22 was the last standalone version of MS-DOS released by Microsoft. It was released in 1994 and was an upgrade from MS-DOS 6.0 and 6.2. MS-DOS 6.22 included various enhancements and utilities over its predecessors, such as improved memory management, disk utilities (like chkdsk and defrag), and enhanced file management capabilities.

During the early 1990s, MS-DOS was a widely used operating system for IBM-compatible personal computers, providing a command-line interface and supporting a variety of applications and games. With the rise of graphical user interfaces (GUIs) like Windows, MS-DOS gradually became integrated into Windows operating systems as a command-line interface rather than being released separately.

Therefore, the correct answer is Option D: 6.22, as it was the last standalone release of MS-DOS.