Do you think that “progressivism era” was accomplished by exploiting the lower class?

No, that is the exact opposite of the progressive era and it’s goals. The main objectives of the Progressive movement were addressing problems caused by industrialization, urbanization, immigration, and political corruption. The movement primarily targeted political machines and their bosses. It focused on the lower class to ensure equality for them. It was meant to defuse exploiting the lower class.

Im pretty sure the answer is d.) is more densely populated.