The correct answer is D: The working poor.
The Gilded Age was the period in the United States, lasting from the 1860's to 1896, where occurred a rapid and important transformation in matters of the economy, society, politics and technology.
By this time, the Gilded Age society consisted of "Two halves", the first half was compound of the upper-class, that included the owners or managers of the industries, and the middle-class, that also had well-paid jobs and supported the upper-class. The other half consisted of working-class families, including immigrants. During this period, U.S. shifted from an agrarian to an industrial economy, therefore the opportunities jobs were in the cities. As a result, millions of farmers and immigrants (the working-class) moved into American's big cities looking for work. Some of the cities: New York, Boston, Philadelphia, St. Louis and Chicago.
However, nearly 40% of the working-class was poor. They had to live in very poor circumstances, the working conditions were dangerous, they'd receive no benefits at all, had to face long hours and the paid wasn't enough.
