The correct answer is C.
'Robber baron'is a derogatory term used for some powerful 19th-century American businessmen. The term was usually applied to businessmen who were viewed as having used illegal or questionable methods to accumulate their wealth. They may have offered their products at exceptionally low prices and pay their workers very low wedges. They would also buy out the competitors and hike up their prices later.
The term 'robber baron ' comes from medieval German. It was popular during the Great Depression regarding American businessmen who amassed great fortunes due to immoral, unethical or illegal means.