Appliance dealer: Appliance manufacturers commonly modify existing models without giving the modified versions new model names. Some people have complained that this practice makes it impossible for consumers to be certain that the appliance they are about to purchase is identical to the one they may have seen at a neighbor' s or read about in a consumer magazine. Yet manufacturers' modifications to existing models are invariably improvements that benefit the buyer. Ttherefore, consumers have little reason to object to this practice. Which one of the following, if true, most seriously weakens the dealer's arguments? ['The high cost of product advertising makes appliance manufacturers generally reluctant to change model names to reflect modifications to their products.', 'Appliances are generally purchased with the expectation that they will continue to be used for several years.', 'Appliances usually carry a model number that provides substantially more detailed information about the product than does the model name.', 'Improved versions of appliances typically become available before vendors have stopped selling the older versions of the appliance with the same model name.']