The closing of the frontier in the early 20th century led eventually t

The closing of the frontier in the early 20th century led eventually to

(a) exhausting the land of all fertility by overusing it.
(b) a change from an “intensive” to an “extensive” use of the land.
(c) an emphasis on water conservation projects and the irrigation of arid lands.
(d) the sale of Bureau of Land Management and Forest Service lands to provide more land
for private agriculture.

ANSWER

(c)