The correct answer is D) the power of business leaders with corrupt political machines.
A major danger to democratic government in the last part of the 19th century was the power of business leaders with corrupt political machines.
Political machines were groups in political parties that had their own interests and agendas. They were corrupt groups formed by rich businessmen that wanted to influence legislation. One of the best examples of a political machine was Tammany Hall in the mid-1800s and its corrupt leader Boss Tweed.