How did big business change at the end of the nineteenth century?

The late nineteenth century saw the ascent of "huge business" in vital ranges of monetary action. ("Huge" is never characterized decisively, yet the quantitative term is famously used to imply something critical.) Big business firms were organizations that utilized administration to control monetary action. Enormous business firms broke themselves into various capacities, or "divisions," and utilized directors to arrange crafted by offices, and "center supervisors" to facilitate work among offices.Railways were the principal "huge organizations" in the United States. After railroad organizations started to work on tracks that extended for fifty and more miles, their proprietors soon understood that they needed to isolate duties among various supervisors, with coordination of the different elements of the organization - from requesting business, to working trains, to looking after offices, to financing everything. By the 1850s railroad officials were idealizing frameworks of administrative control over their always complex firms.

by improved communication.

i would say b. or c.