The correct answer is A) The establishment of large farming corporations; barbed wire.
The statement that best explains why the era of open-range cattle ranching had ended in the West by the 1890s is "The establishment of large farming corporations; barbed wire."
During the era of open-range cattle, cows used to roam freely in big portions of land. Cowboys also herded cows throughout long distances. Cowboys took the animals to train stations to be transported to other places to be sold. But this practice ended when farmers put a barbed wire to protect their private properties.