How was Rockefeller able to build his monopoly across the oil industry? He found newer and cheaper ways to refine oil, increasing his profits.
He confined his business to Ohio so he could buy all the refineries there.
He bought up oil refineries, cut costs, and reinvested his profits in other refineries.
He began to sell kerosene as well as oil, expanding his market.

the answer c

Explanation: I just did it and it was right

C. He bought up oil refineries, cut costs, and reinvested his profits in other refineries.

Explanation:

the number of calories in each pack of cookies has a greater variation than the number of calories in each pack of crackers.

the right choice would be a. culture within the city-state. c. loyalty to the police. d separation by land and sea.