When mark twain and charles dudley warner labeled the post–civil war era the "gilded age," they implied that it was characterized by: a. massive appreciation of art and culture. b. such widespread diffusion of wealth that more people had access to real gold. c. widespread greed and corruption. d. the practical elimination of poverty?

C. Widespread greed and corruption. 

The term Gilded Age referred to the glitz and glamour of the time period but also indicated only a few had access to the money of the time. Many came to America for the "streets paved in gold" but rather found they were paved in horse feces and filth. The upper class were beyond wealthy and used unfair methods to gain that wealth. 

And this too use this if needed