Answer is B. Increased runoff carries fertilizers.
Runoff is movement of water over land as surface water instead of being absorbed into groundwater or evaporating. Runoff is that part of the precipitation, irrigation water that appears in uncontrolled surface streams, rivers, drains, or sewers. When runoff flows along the ground, it carries soil contaminants such as fertilizers, pesticides to other parts of land that become discharge or overland flow.
