A recent study reveals that television advertising does not significantly affect children' s preferences for breakfast cereals. The study compared two groups of children. One group had watched no television, and the other group had watched average amounts of television and its advertising. Both groups strongly preferred the sugary cereals heavily advertised on television. Which one of the following statements, if true, most weakens the argument? ['Cereal preferences of adults who watch television are known to be significantly different from the cereal preferences of adults who do not watch television.', 'Both groups rejected cereals low in sugar even when these cereals were heavily advertised on television.', 'The preference for sweets is not a universal trait in humans, and can be influenced by environmental factors such as television advertising.', 'The preferences of children who do not watch television advertising are influenced by the preferences of children who watch the advertising.']