Question

how did john d. rockefeller horizontally integrate his monopoly in 1882?
he purchased iron mines around the country to add to his business.
he created a trust that controlled oil wells, refineries, and distribution networks.
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.

Explanation:

Horizontal integration involves acquiring or merging with competitors in the same industry. Rockefeller's Standard Oil used a trust (a legal arrangement) to control a large portion of oil refineries (a key part of the oil - related production process at that time). Purchasing iron mines or coal plants is vertical integration (moving into different stages of production or different raw materials). Controlling oil wells, refineries, and distribution networks is more of a vertical integration (covering different stages of the oil production and distribution chain).

Answer:

He created a trust that controlled ninety percent of the nation’s oil refineries.