Reread these two excerpts from “The Pony Express” Chapter 1 and answer the question that follows:

By 1860, then, war was inevitable. Naturally, the conflict would at once present intricate military problems, and among them the retention of the Pacific Coast was of the deepest concern to the Union. Situated at a distance of nearly two thousand miles from the Missouri River which was then the nation's western frontier, this intervening space comprised trackless plains, almost impenetrable ranges of snow-capped mountains, and parched alkali deserts. And besides these barriers of nature which lay between the West coast and the settled eastern half of the country, there were many fierce tribes of savages who were usually on the alert to oppose the movements of the white race through their dominions.

and

Yet it [the Pony Express] was of the greatest importance in binding the East and West together at a time when overland travel was slow and cumbersome, and when a great national crisis made the rapid communication of news between these sections an imperative necessity.

Which idea do both of these excerpts focus on?

The difficulties associated with travel to the West coast
The role the Pony Express played in starting the national crisis
The historical context around the country at the time of western expansion
The relationship between the military and the fierce tribes