Which industrialist is known for dominating the oil industry through horizontal integration?

John D. Rockefeller is recognized for dominating the oil industry through the practice of horizontal integration, which involves consolidating many companies that produce the same product into a single corporation. This strategy allowed him to eliminate competition and gain significant control over the oil market in the United States during the late 19th century. By acquiring or merging with other oil companies, Rockefeller was able to lower production costs and stabilize prices, ultimately leading to the creation of the Standard Oil Company, which became a powerful monopoly in the oil industry.

In contrast, the other individuals mentioned in the options were known for different industries and strategies. Andrew Carnegie focused on vertical integration in the steel industry, where he controlled every aspect of production from raw materials to distribution. Cornelius Vanderbilt was primarily involved in the railroad and shipping industries, utilizing his wealth and business acumen to dominate transportation. Henry Ford is famously associated with revolutionary methods of automobile manufacturing, particularly his use of assembly line techniques to mass-produce cars. Each of these industrialists made significant contributions to their respective fields, but Rockefeller's legacy is particularly linked to horizontal integration in the oil industry.