Question ID:PT28 S1 Q12 Passage:     People who say that Dooney County is flat are clearly wrong.  On flat land, soil erosion by water is not a problem.  Consequently, farmers whose land is flat do not build terraces to prevent erosion.  Yet I hear that the farms in Dooney County are dotted with terraces. Stem:The author's conclusion in the passage depends on the assumption that Correct Answer Choice:BChoice A:the only cause of soil erosion is water Choice B:there are terraces on farmland in Dooney County which were built to prevent soil erosion Choice C:terraces of the kind found on farmland in Dooney County have been shown to prevent soil erosion Choice D:on flat land there is no soil erosion Choice E:the only terraces in Dooney County are on farmland