After Exploring Much of the West, Geologist John Wesley Powell

After exploring much of the West, geologist John Wesley Powell advised in 1874 that

A) the rush of settlers was devastating the western environment.
B) land west of the 100^th meridian could not be farmed without extensive irrigation.
C) damming western rivers for irrigation purposes would damage mountains and forests.
D) mining was the only industry that could sustain the western economy.
E) irrigation was not necessary for farming west of the 100^th meridian because of adequate rainfall and fertile lands in this region.