What was the core business that made Standard Oil a horizontally integrated monopoly?

finding new uses for oil

refining oil

building oil pipelines

transporting oil to customers

It was an American oil producing, That was transporting, refining, and marketing company. And was established in 1870 by John Rockefeller as a corporation in Ohio Its controversial history as 1 of the worlds 1st and largest multinational corporations ended in 1911, when the U. S. Supreme Court ruled that standard was an illegal monopoly.