The answer is option D. Populists wanted to use silver as well as gold to increase the money supply to help struggling farmers.
The Populist movement was created to help farmers that could not solve their financial problems. The way in which they though that they will be able to increase the money supply was through the use of silver as well as gold. People were confident in their money because it would be backed by something that had value (gold and silver). Through this, they hoped to achieve a more equitable economy and also bring about social reforms.
"Irredentism is any political or popular movement that seeks to claim/reclaim and occupy a land that the movement's members consider to be a "lost" territory from their nation's past. Wikipedia"
