-scale parameter is optional. We can scale at which to deliver results. Unless specified, this command returns all data in bytes.
d) db.runCommand( command ) - Provides a helper to run specified database commands. This is the preferred method to issue database commands, as it provides a consistent interface between the shell and drivers.
-command - A database command, specified either in document form or as a string. If specified as a string, db.runCommand() transforms the string into a document.