Dental researchers recently discovered that tooth-brushes can become contaminated with bacteria that cause pneumonia and strep throat. They found that contamination usually Occurs after toothbrushes have been used for four weeks. For that reason, people should replace their toothbrushes at least once a month.
Which of the following, if true, would most weaken the conclusion above?
A. The reason for contamination is irrelavant to the fact that toothbrushes do get contaminated. B. Other contaminations has nothing to do with the recommendation to replace tootbrushes due to bacterial contamination. Again irrelavant information. D. The uneffective method that people use to try to prevent contamination is irrelavant to the recommendation. E. The severity of contamination after a longer period of time, namely 6 weeks, doesn't change the fact that toothbrushes are still contaminated after 4 weeks. It doesn't help/weaken the recommendation.