Your answer would be B). economic concerns like the gold standard and protective tariffs.
William McKinley and the Republican Party wanted the U.S to keep using the "gold standard" system. The gold standard system is a system where someone's account balanced is based off of a quantity of gold that they have. But, William Jennings Bryan and the populist were leaning toward the "free silver" system. The free silver system was a system that helped the poor farmers from the South and West to get America out of depression. During the election, the decisions was based on what kind of system people wanted U.S to go by, either the "gold standard" or the "free silver" system.