Answer:
a. the development of railroad cars that could haul cattle.
Explanation:
The abrupt end of long distance cattle drives in 1885 was primarily due to the development of railroad cars that could haul cattle.
It was the advent of expanding rail road lines that terminated the cattle drive through Kansas because the end points of the cattle trail shifted to meet expanding railroad lines.
It was logical that as the railroads expanded to meet the cattle drive, one had to give way to the other because cattle do stray and trains could haul cattle
