这题应该是E。 The stem says although asbestors is the primary cause, the virus is contributing to the cause of cancer as well. Researchers say the polio vaccine that was contaminated in 1960 is the cause. We need to show that SV40 did not come from any other source but the vaccine
A - doesn't strengthen researcher's argument, virus could originate from research lab B - could be true as contamination does not happen now, but may have happened in 1960 - however is that the only source? its been a long time since 1960.. C - could be true - but we already know this from stem D - ok, that means that the virus alone could be causing the cancer E - this shows that in finland, if it was not the vaccine, there are no other sources of the virus that could lead to cancer |