The correct answer is C) They supported the direct election of U.S. Senators.
One of the voting reforms that the Populists advocated was "they supported the direct election of U.S. Senators."
The populist had a well defined political platform that convinced a considerable portion of Americans. The populist supported the direct election of Senators, the free coinage of silver, total support for farmers in debt, a graduated income tax that helped people suffering from economic problems, the abolition of the national bank, the permanent print of paper money, and the ownership of the means of transportation by the government, the creation of pensions for workers and the reduction of the working day to 8 hours.