I think it’s A but I’m not sure
Explanation:
The period between 1870 and 1900 in the United States is known as the “Gilded Age” and was characterized by economic and industrial growth, increased political participation, immigration, and social reform.
I would say B.
I hoped I help have a nice day
Positive: <span>faster and safer transportation from coast to coast, larger amount of goods ship faster, cheaper for travel, and helped unpopulated areas get settled easier
Negative: Buffalo were killed in large numbers, Natives lost their land, and brought a lot of western settlers take over native lands.</span>