answer choice A

Hi @annasc, Happy to help! We know that all winners of Nobel prizes for science have made contributions to science. We also know that these winners are typically professional scientists but that amateur scientists have also made many significant contributions. Answer choice (A) is incorrect because we do not know if the amateur scientists who have made significant contributions to science have all also won Nobel prizes. We know that the winners are typically professional scientists; this means that some winners have been amateur scientists. If all the amateur scientists who made significant contributions to science have won Nobel prizes, then it is not true that some amateur scientists who made significant contributions to science have not won Nobel prizes. Hope this helps! Please let us know if you have any further questions.