A river, such as the one in the diagram, receives pollution from all the different sources shown. The types of pollutants and the amounts that enter the river will be different, but all the sources contribute to pollution of this freshwater. . Which sources of pollution are point sources?
A. factories, cropland
B. wastewater treatment plants, factories
C. urban streets, suburban development
D. urban streets, suburban development, rural homes, cropland, animal feedlot