Question ID:PT64 S1 Q22 Passage:Microbiologist: Because heavy metals are normally concentrated in sewage sludge during the sewage treatment process, the bacteria that survive in the sludge have evolved the unusual ability to resist heavy-metal poisoning. The same bacteria also show a strong resistance to antibiotics. This suggests that the bacteria's exposure to the heavy metals in the sewage sludge has somehow promoted their resistance to antibiotics. Stem:Which one of the following, if true, most strengthens the microbiologist's argument? Correct Answer Choice:BChoice A:Most bacteria that are not resistant to antibiotics are not resistant to heavy-metal poisoning either. Choice B:Bacteria that live in sewage sludge that is free of heavy metals, but is in other respects similar to normal sewage, are generally resistant to neither heavy-metal poisoning nor antibiotics. Choice C:Antibiotic resistance of bacteria that survive in sewage sludge in which heavy metals are concentrated contributes to their resistance to heavy-metal poisoning. Choice D:Sewage sludge that contains high concentrations of heavy metals almost always contains significant concentrations of antibiotics. Choice E:Many kinds of bacteria that do not live in sewage sludge are resistant to both heavy-metal poisoning and antibiotics.