Question ID:PT92 S1 Q10 Passage:Dentist:  Five recently conducted studies all show that the proportion of children with decayed, missing, or filled teeth is lower in Europe, where water is not fluoridated, than in the United States, where it is. This is convincing evidence that fluoridation of water does not have a substantial tendency to prevent tooth decay. Stem:Which one of the following, if true, would most strengthen the dentist's argument? Correct Answer Choice:EChoice A:Toothpaste containing fluoride is widely available in both the United States and Europe. Choice B:Nearly all dentists in the United States use dental treatments involving the application of fluoride directly to tooth surfaces. Choice C:Dental hygiene is typically taught in elementary school in both Europe and the United States. Choice D:On average, children in Europe receive dental checkups more frequently than children in the United States. Choice E:The diets of children in the United States are not generally worse for teeth than those of children in Europe.