Well, ''Order'' means quite a lot so I am unsure what response they are looking for.
Order: an authoritative command to do something.
Order: a request for something.
Order: a state of in which everything is in its correct place.
Order: a particular social class, group or society.
Order: a judge can call for silence using this word.
Take your pick and I hope you get it right and enjoy your discount. If not, well, we tried! ;)