For centuries, mathematics seemed to exist in service to the natural sciences. Many of the great mathematical breakthroughs, like Newton' s Calculus, were spearheaded in the effort to solve scientific questions. In the nineteenth century, though, mathematicians made it clear that the primary object of mathematical study were the abstract creations of mathematics-numbers and shapes and functions and their more abstruse extensions-irrespective of whether this study has any bearing on scientific investigation. Ttherefore, mathematics is not properly one of the natural sciences. Which of the following is an assumption that supports drawing the conclusion above from the reasons given for that conclusion? ['The object of a natural science must be something tangible that can be perceived by the senses.', 'Some great scientists, like Einstein, by their own admission, were not very good at math.', 'Mathematics can also be used to serve social sciences, such as economics.', 'If one discipline serves another discipline, it can never rise to the same rank as the discipline it serves.']