Which of the following file names are invalid in MSDOS?

Solution (By Examveda Team)

In MS-DOS (and generally in file systems), filenames have certain rules and restrictions regarding valid characters and format:

MYFILE.DOS: This filename is valid. It follows the convention of using letters, numbers, and the dot (.) separator, which is standard for file extensions.
CHECK$.(1): This filename is valid. It uses letters, numbers, and special characters like "$" and "(", which are allowed in MS-DOS filenames.
Verified.###: This filename is valid. It uses letters, numbers, and the dot (.) separator, with numbers and the pound sign (#), which are allowed in filenames.
Qwerty.1?3: This filename is invalid. The "?" character is not allowed in MS-DOS filenames. MS-DOS restricts filenames to letters, numbers, and a few special characters like dot (.) and underscore (_).

Therefore, the correct answer is Option D: Qwerty.1?3.