The number one thing that helped spread the belief was the population growth. America need more room for more immigrants.
The term is Books of Hours. Hope its the answer your looking for.
The answer is a.
The Populist Party was originally formed by farmers in response to the growing threat big companies had on them. So that rules out b through d.
If you want me to give you a more detailed explanation of the Populist Party, let me know because I just had a final on this in college. :)
