Which of the following is a characteristic of robber barons? paid their workers high wages used unfair business practices donated money to public libraries and schools

The correct answer is used unfair business practices

This term, robber barons, was used in the 19th century to describe businessmen who became so wealthy that they formed things like monopolies or cartels and rigged the market and exploited numerous loopholes in the system to only become even wealthier. They were criticized because of this and the government had to interfere.