Critical Reasoning

Psychological research indicates that college hockey and football players are more quickly moved to hostility and aggression than are college athletes in noncontact sports such as swimming. But the researchers’ conclusion—that contact sports encourage and teach participants to be hostile and aggressive—is untenable. The football and hockey players were probably more hostile and aggressive to start with than the swimmers.
Which of the following, if true, would most strengthen the conclusion drawn by the psychological researchers?
(A) The football and hockey players became more hostile and aggressive during the season and remained so during the off-season, whereas there was no increase in aggressiveness among the swimmers.
(B) The football and hockey players, but not the swimmers, were aware at the start of the experiment that they were being tested for aggressiveness.
(C) The same psychological research indicated that the football and hockey players had a great respect for cooperation and team play, whereas the swimmers were most concerned with excelling as individual competitors.
(D) The research studies were designed to include no college athletes who participated in both contact and noncontact sports.
(E) Throughout the United States, more incidents of fan violence occur at baseball games than occur at hockey or football games.
A