Question ID:PT20 S1 Q4 Passage:An ingredient in marijuana known as THC has been found to inactivate herpesviruses in experiments.  In previous experiments researchers found that inactivated herpesviruses can convert healthy cells into cancer cells.  It can be concluded that the use of marijuana can cause cancer. Stem:Which one of the following, if true, most seriously weakens the argument? Correct Answer Choice:BChoice A:Several teams of scientists performed the various experiments and all of the teams had similar results. Choice B:The carcinogenic effect of THC could be neutralized by the other ingredients found in marijuana. Choice C:When THC kills herpesviruses it weakens the immune system, and it might thus diminish the body's ability to fight other viruses, including viruses linked to cancers. Choice D:If chemists modify the structure of THC, THC can be safely incorporated into medications to prevent herpes. Choice E:To lessen the undesirable side effects of chemotherapy, the use of marijuana has been recommended for cancer patients who are free of the herpesvirus.