Final answer:
The late 1800s populist demands for regulation of railroad charges and coinage of silver reflected the concerns of American farmers, who were struggling economically and sought financial relief through increased money supply and political representation through the Populist Party.
Step-by-step explanation:
The demands for the regulation of railroad shipping charges, free and unlimited coinage of silver, and other monetary reforms in the late 1800s most reflected the concerns of American farmers. These demands highlight the economic difficulties faced by farmers, such as the deflationary pressure of a gold standard that limited the amount of money in circulation, which made it harder to pay off debts.
The Populist Party arose in response to these issues, advocating for policies such as bimetallism to increase the money supply and help farmers cope with lower crop prices and high tariffs. Despite some legislative efforts like the Sherman Silver Purchase Act and the Sherman Anti-Trust Act, the government's actions were largely ineffective in addressing the farmers' needs, leading to increased political activism and the eventual rise of William Jennings Bryan as a presidential candidate who supported the silver standard.