Essayist: Winners of a Nobel prize for science, who are typically professional scientists, have all made significant contributions to science. But amateur scientists have also provided many significant contributions. And unlike professional scientists, who are often motivated by economic necessity or a desire for fame, amateur scientists are motivated by the love of discovery alone. If the essayist's statements are true, then which one of the following must also be true? ['The love of discovery is the motive behind many significant contributions to science.', 'Typically, winners of a Nobel prize for science are not motivated at all by the love of discovery.', 'A professional scientist is more likely to make a significant contribution to science if he or she is motivated by the love of discovery.', 'Some amateur scientists who did not win a Nobel prize for science nevertheless made significant contributions to science.']