Answer:One likely effect of Standard Oil's business practices was that competition in the oil market diminished. By buying out most of its rivals and controlling 90% of the petroleum refineries in the United States, Standard Oil was able to establish a dominant position in the market and reduce competition. This may have led to higher prices and less choice for consumers, as Standard Oil would have had less incentive to compete with other companies and offer competitive prices.
The other options provided are not likely effects of Standard Oil's business practices. The company may not have set limits on its prices, as this would have reduced its ability to maximize profits. The company may not have increased its efforts to attract needed customers, as it already had a dominant position in the market and did not need to compete for customers. And the federal government is not likely to have offered a subsidy to make the company more competitive abroad, as this would have been seen as favoring one company over others and potentially violating antitrust laws.
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