Which of the following file names are invalid in MSDOS?

MYFILE.DOS

CHECK$.(1)

Verified.###

Qwerty.1?3

Answer

Answer: Option D

Solution

Answer: Option D

Solution:

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 $. (1) :< / s t r o n g > T hi s f i l e nam e i s v a l i d . I t u ses l e tt er s, n u mb er s, an d s p ec ia l c ha r a c t er s l ik e "$ " 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.