Which person is given as an example of a monopoly?

• A. Andrew Carnegie
• B. Cornelius Vanderbilt
• C. J.P. Morgan
• D. John D. Rockefeller: Founder of Standard Oil

Answer: (D)

A monopoly occurs when one firm dominates a market, controlling most or all of the supply and having power to influence prices. John D. Rockefeller, founder of Standard Oil, is the classic example because his company built extensive horizontal consolidation and used its size and agreements with railroads to control a dominant share of oil refining and distribution in the United States. That level of market control—enabling price setting and limiting competition—is exactly what defines a monopoly, which is why Rockefeller is the best illustration. The other figures were powerful in their sectors, but Rockefeller’s Standard Oil is the one most closely associated with monopoly power in American history, including the eventual legal breakup under antitrust law.