How did John d Rockefeller horizontally integrate his monopoly in 1889

He created a trust that controlled ninety percent of the nations oil refineries. He purchased coal plants around the country to add to his business

the answer would be option c. the chief result of u.s. participation in world war i is that, the u.s. forces ended the stalemate and led to an allied victory. after the us joined wwi, the allies had the forces they need to triumph. hope this is the answer that you are looking for.

explanation:

mark brainliest and have a great day!