Question ID:PT72 S3 Q7 Passage:In one study, hospital patients' immune systems grew stronger when the patients viewed comic videos. This indicates that laughter can aid recovery from illness. But much greater gains in immune system strength occurred in the patients whose tendency to laugh was greater to begin with. So hospital patients with a greater tendency to laugh are helped more in their recovery from illness even when they laugh a little than other patients are helped when they laugh a greater amount. Stem:The argument is most vulnerable to criticism on the grounds that it Correct Answer Choice:AChoice A:overlooks the possibility that the patients whose tendency to laugh was greater to begin with laughed more at the comic videos than did the other patients Choice B:fails to address adequately the possibility that the patients whose tendency to laugh was greatest to begin with already had stronger immune systems than the other patients Choice C:presumes, without providing justification, that hospital patients have immune systems representative of those of the entire population Choice D:takes for granted that the gains in immune system strength did not themselves influence the patients' tendency to laugh Choice E:presumes, without providing justification, that the patients whose tendency to laugh was greatest to begin with recovered from their illnesses more rapidly than the other patients