J. J. Thomson, the discoverer of the electron and a recipient of the Nobel Prize in physics, trained many physicists, among them seven Nobel Prize winners, 32 fellows of the Royal Society of London, and 83 professors of physics. This shows that the skills needed for creative research can be taught and learned. Which one of the following is an assumption on which the argument depends? ['At least one of the eminent scientists trained by J. J. Thomson was not a creative researcher before coming to study with him.', 'Scientists who go on to be the most successful researchers often receive their scientific education in classes taught by renowned research scientists.', 'J. J. Thomson was an internationally known physicist, and scientists came from all over the world to work with him.', 'All the scientists trained by J. J. Thomson were renowned for their creative scientific research.']