When people are told that some behavior is common, they are more likely to indulge in that behavior even when society disapproves of it. For example, if many people are shown littering in an anti-litter advertisement, observers may subconsciously feel that littering is a normal, accepted activity. Thus, in order to influence behavior effectively, it is critical not to show or discuss anyone engaging in an activity that the advertisement seeks to discourage.

Which of the following, if true, most undermines the argument’s conclusion?

(A) In a study, the most effective anti-smoking advertisement featured a person smoking amidst a disapproving crowd.
(B) The most effective way to influence behavior is for parents to teach their children not to litter.
(C) People who watch public service advertisements are typically aware that actors are merely pretending to engage in the disapproved behavior.
(D) Teenagers are more likely to litter than the general population and less likely to be influenced by anti-litter advertisements.
(E) In a study, the most effective anti-littering advertisement featured a pristine public park with children playing in the background.