D) Economic growth and social change.
The Gilded Age was a period in the United States, lasting from the 1860s to 1900, where occurred a rapid and important transformation in matters of the economy, society, politics, and technology.
Some of the changes included: Shifting from an agrarian to an industrial economy, which led many moved into American's big cities, small businesses grew larger, the corporation became the dominant form of business organization, industrialists, bankers and politicians enjoyed extraordinary wealth (many in a corrupt way) at the expense of the working class, A national transportation and communication network was created, among others.
