Which of the following statements about the persian empire is true? a. some of the rulers allowed people to practice their own religion b. there was an extensive network of roads c. a religious man founded a monotheistic religion d. all of the choices are correct

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.