The correct answer to this open question is the following.
The question does not include options. We do not know the name of the individuals you are referring to. You also did not mention what period in the history of the US you are referring to.
So although your question is incomplete, we can help you answer in the following general terms.
We assume you are referring to the Progressive era in the United States history from the 1880s to the 1920s.
During this era, many reformers demanded changes in US politics and economics. After many injustices lived during the Gilded Age, muckraker journalists exposed the corruption activities of many legislators and politicians. The federal government created legislation to stop this situation and also created laws to eliminate monopolies in the economy.
So we can say that reformers built a foundation to change the political and economic scene in the US, as well as society.
