In recent years, many cabinetmakers have been winning acclaim as artists. But since furniture must be useful, cabinetmakers must exercise their craft with an eye to the practical utility of their product. For this reason, cabinetmaking is not art. Which of the following is an assumption that supports drawing the conclusion above from the reason given for that conclusion? ['Some furniture is made to be placed in museums, where it will not be used by anyone.', 'Artists are not concerned with the monetary value of their products.', 'Cabinetmakers should be more concerned with the practical utility of their products than they currently are.', "An object is not an art object if its maker pays attention to the object's practical utility."]