The command used to seek for assistance in Microsoft Disk Operating System (DOS) is "/?".

The /? switch is a universal switch that can be used with most MS-DOS commands to get help about the command. To use the /? switch, simply type the command followed by the /? switch and press Enter. For example, to get help about the attrib command, you would type:

attrib /?
This will display a help screen that describes the attrib command and its options.

The other options are incorrect. Helper is not a valid MS-DOS command. Attrib is a command that is used to change the attributes of files. /S is a switch that is used to specify that the command should be applied to all files in a directory and its subdirectories.