Final answer:
McClure's was the magazine that published articles by muckrakers such as Lincoln Steffens, Ida Tarbell, and Upton Sinclair.
Step-by-step explanation:
The correct answer is c. McClure's. McClure's was a magazine that published articles by muckrakers such as Lincoln Steffens, Ida Tarbell, and Upton Sinclair. These muckrakers were investigative journalists who exposed social and political corruption in the early 20th century. McClure's magazine played a significant role in the Progressive Era by raising awareness about these issues and helping to bring about reforms.
Learn more about McClure's magazine and muckraker journalists