The use of growth-promoting antibiotics in hog farming can weaken their effectiveness in treating humans because such use can spread resistance to those antibiotics among microorganisms. But now the Smee Company, one of the largest pork marketers, may stop buying pork raised on feed containing these antibiotics. Smee has 60 percent of the pork market, and farmers who sell to Smee would certainly stop using antibiotics in order to avoid jeopardizing their sales. So if Smee makes this change, it will probably significantly slow the decline in antibiotics' effectiveness for humans. Which of the following, if true, would most strengthen the argument above? ['A phaseout of use of antibiotics for hogs in one country reduced usage by over 50 percent over five years.', "If Smee stops buying pork raised with antibiotics, the firm's costs will probably increase.", 'Other major pork marketers will probably stop buying pork raised on feed containing growth-promoting antibiotics if Smee no longer buys such pork.', 'The decline in hog growth due to discontinuation of antibiotics can be offset by improved hygiene.']