The retail price of decaffeinated coffee is considerably higher than that of regular coffee. However, the process by which coffee beans are decaffeinated is fairly simple and not very costly. Ttherefore, the price difference cannot be accounted for by the greater cost of providing decaffeinated coffee to the consumer. The argument relies on assuming which one of the following? ['Processing regular coffee costs more than processing decaffeinated coffee.', 'Retail coffee-sellers do not expect that consumers are content to pay more for decaffeinated coffee than for regular coffee.', 'Price differences between products can generally be accounted for by such factors as supply and demand, not by differences in production costs.', 'The beans used for producing decaffeinated coffee do not cost much more before processing than the beans used for producing regular coffee.']