Why not b?

Hi @andreaskormusis, Thanks for the question! (B) is wrong because it’s slightly too strong. We don’t need to assume that physicians have a “more” direct effect on the lives of others than air traffic controllers and nuclear power plant operators. They could have an equal amount of effect. So negating (B) doesn’t necessarily weaken the argument, and so it’s not the necessary assumption we need. Hope this helps! Feel free to ask any other questions that you might have.