Concept:A valid folder name must not contain characters reserved by the operating system, such as /, :, or *.Explanation:Option A: Black/stars contains a slash /, which separates folders, so it is invalid.Option B: Black stars uses only a space, which is allowed in a folder name.Option C: Black:stars contains a colon :, which is invalid.Option D: Black* contains an asterisk *, which is invalid.Answer:B. Black stars