Which of the following most contributed to the decline of the ranching industry in the late 1880s?
the invention of barbed wire
an oversupply of cattle
ranchers’ refusal to use technology
a series of heavy rains

The answer would be : ranchers' refusal to use technology. During the late 1880s, the technologies began to rapidly developed within the industry. But back then, a lot of ranchers are really comfortable in using traditional ways (using slaves) and they refuse to use technology

Internal combustion engines