The correct answer is Muckrakers.
Muckraker is the name give to a group of American journalists of the Progressive Era (1890s–1920s) who tried to expose corruption in big business and in government. One of the most famous muckraking magazines was McClure's, which tried to raise awareness about the social hardships (poverty, unsafe working conditions, etc.) caused by the power of big business in a rapidly industrializing United States.