How do refrigeration and improved transportation affect the von Thunen model of land use? A. They make it obsolete because perishable items now can be grown farther away from the city center. B. They reinforce it because the theory assumes that settlements grow along transportation routes, such as highways and railroads. C. These are the central components on which the theory is based. D. They don't affect the theory, because the theory is focused on urban settlement. Please select the best answer from the choices provided. A B C D