Which of the following, if true, most seriously undermines the argument? A. Several kinds of fat substitute are available to manufacturers, each of which gives a noticeably different taste and texture to products that contain it. B. The products made with artificial sweeteners did not taste like products made with sugar. C. The foods brought out in sugar-free versions did not generally have reduced levels of fat, but many of the fat-free versions about to be introduced are low in sugar. D. People who regularly consume products containing artificial sweeteners are more likely than others to consume fat-free foods. E. Not all foods containing fat can be produced in fat-free versions.