USA HISTORY

Detailed explanation-1: -Rockefeller built an oil monopoly by ruthlessly eliminating most of his competitors. This made him the richest man in the world.

Detailed explanation-2: -Standard Oil gained a monopoly in the oil industry by buying rival refineries and developing companies for distributing and marketing its products around the globe. In 1882, these various companies were combined into the Standard Oil Trust, which would control some 90 percent of the nation’s refineries and pipelines.

Detailed explanation-3: -Standard Oil (in full, Standard Oil Company and Trust) was an American company and corporate trust that from 1870 to 1911 was the industrial empire of John D. Rockefeller and associates, controlling almost all oil production, processing, marketing, and transportation in the United States.