Why was the cleveland massacre significant in the formation of standard oil?
standard oil significantly improved its business practices after the cleveland massacre.
standard oil was bought out by other cleveland companies after the massacre.
standard oil closed down after the cleveland massacre.
standard oil became a monopoly in the cleveland oil market after the massacre.

Correct answer choice is :

The Cleveland Massacre was the secondary plan of Rockefeller to corner the oil exchange of the United States of America. During the early 1870’s near the oil fields of Pennsylvania, various oil refining companies struggled with each other. The heavy competition for the black oil made pricing unpredictable. Some companies were willing to give expensive prices just to get an edge on the competition.

la segunda guerra mundial comenzó el 1 de septiembre de 1939 y terminó el 2 de septiembre de 1945. ¡espero que esto ayude!