Answer:
They developed the idea of creating trusts.
Explanation:
The Standard Oil Company was at its time the largest oil refinery and it was a monopoly created by Rockefeller and his associates, trusts were basically an agreement between several smaller corporations to cooperate between them to generate revenue and profit for all of them, it was basically an agroupation among several companies that had a common goal, it was labeled as a monopoly after several legal battles and had to be dissolved.
