What percent of the nation's oil business did Standard Oil Company control?

A) 50

B) 75

C) 90

D) 100

C) 90

Explanation:

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.