Only filenames and extensions are to be displayed in wide format, which command you'll use?

Answer: Option A

Dir/w only displays the file names and extensions excluding file created date/time, file size. Second option dir a: will list the contents of A drive (floppy drive), third dir/s lists current directory and its sub-directories too, dir/b displays bare format, that means, it just makes a list of files, no more information.