Beginning About 2000 B

Beginning about 2000 B.C.E., what man-made environmental crisis wreaked havoc on Mesopotamian political stability?

A) The runoff of raw sewage from towns seeped into the water table, causing illness and death.
B) Overconstruction of irrigation canals in northern city-states left southern city-states without water.
C) Intensive irrigation elevated the salt level of the soil, which decreased its fertility and lowered crop yields.
D) Intensive mining in the north led to erosion and disastrous flooding.