The answer is "b. Credit Mobilier".
The Gilded age refers to the time period which is assumed an imperative role in the advancement of the American culture. The Gilded Age is a time of American history somewhere in the range of 1870 and 1900. This term was begat by Mark Twain in the late 1800s. The Gilded Age is notable for its political outrages and indulgent presentations of riches. In the meantime, this was a time of real accomplishments in the business and economy, which fundamentally changed existence of American individuals. The Gilded Age was trailed by the Progressive Era which kept going from the 1890s to the 1920s.
