Gilbert: This food label is mistaken. It says that these cookies contain only natural ingredients, but they contain alphahydroxy acids that are chemically synthesized by the cookie company at their plant. Sabina: The label is not mistaken. After all, alphahydroxy acids also are found occurring naturally in sugarcane. Which one of the following, if true, would most strengthen Sabina's argument? ['All substances except those that do not occur naturally in any source are considered natural.', 'Many other foods advertising all natural ingredients also contain some ingredients that are chemically synthesized.', 'The label was printed before the cookie company decided to switch from sugarcane alphahydroxy acids to synthesized ones.', 'Not all chemicals that are part of the manufacturing process are ingredients of the cookies.']