By the mid-1880s, cattle raising in the American West:
a. remained highly successful using open-range techniques.
b. had precluded settlement of the area by farmers.
c. faced numerous problems from both man and nature.
d. proved highly profitable for the legendary cowboys.

C. Faced numerous problems from both man and nature.

Explanation:

There were various factors that brought the Cattle to an end in 1880's. As it was a profitable business it allowed the ranchers to increase the size of their herds that led to over production. Foreign competition and availability of more beef on the market led to the fall in prices.

The harsh winters of 1886 and 1887 coupled with droughts took toll on the cattle herds in Great Plains and forced the ranchers to adopt new techniques. The trend in cattle rearing shifted toward raising them towards smaller ranches.

Cattlemen started to fence manageable herds ( Average 200) fed them grain and hay in winters and turned toward selective breeding to increase the amount of beef. The highly successful open-range techniques came to an end.

Invention of barbed wire affected the cattle drives as the settlers used barbed wire to fence their property, the fences blocked cattle trails. Increase in number of cattle and lack of open lands caused overcrowding of cattle.

your answer would be 12 stories

c it says nothing about connecting those 2 seas.