Which muckraker exposed Standard Oil and helped drive antitrust reform?

• A. Ida Tarbell
• B. Lincoln Steffens
• C. Upton Sinclair
• D. Jacob Riis

Answer: (A)

Tarbell’s investigative reporting embodies muckraking aimed at monopolies and antitrust reform. She produced a detailed, well-sourced history of the Standard Oil Company for McClure’s Magazine, showing how Rockefeller’s empire used rebates, railroad deals, and ruthless tactics to crush competitors and rig the oil market. This vivid exposure helped shift public opinion and provided momentum for antitrust actions, contributing to the eventual breakup of Standard Oil under the Sherman Antitrust Act in 1911. While the other muckrakers advanced important reforms in different areas—Steffens exposed urban political corruption, Sinclair revealed abuses in the meatpacking industry and spurred food safety laws, and Riis documented urban poverty—the direct link to exposing Standard Oil and pushing antitrust reform is Tarbell.