Which of the following most logically completes the passage below?

One name-brand cereal manufacturer is about to reduce wholesale prices for its cereals by 20 percent because consumers have been switching from its cereals to cheaper store brands. The success of this strategy relies on the assumption that supermarkets will pass on all of the savings by lowering the prices they charge consumers for the manufacturer's cereals. Although supermarkets usually pass on such savings, in this case it is likely that supermarkets not do so because __________.