Department store manager: There is absolutely no reason to offer our customers free gift wrapping again this holiday season. If most customers take the offer, it will be expensive and time-consuming for us. On the other hand, if only a few customers want it, there is no advantage in offering it. Which one of the following is an assumption required by the department store manager's argument? ['It would be expensive to inform customers about the free gift wrapping service.', 'Gift wrapping would cost the store more during this holiday season than in previous holiday seasons.', 'Either few customers would want free gift wrapping or most customers would want it.', 'Anything that slows down shoppers during the holiday season costs the store money.']