According to paragraph 4, which of the following is NOT true of commercial activity in ancient Mesopotamia A. Perhaps 20 percent of the population was involved in commercial activity rather than food production. B. Commercial exchanges took place not only between urban and rural areas, but also between cities. C. Although most urban centers had marketplaces, the largest ones were located in southern Mesopotamia. D. Goods were plentiful and widely available to inhabitants of Mesopotamian cities.