Based on the context of the Populist Party's formation and platform, the best reason explaining why farmers and industrial workers supported the Populist Party would be:
B. to limit corporations from controlling the American economy.
The Populist Party sought to address the concerns of farmers and industrial workers who felt marginalized by large corporations and monopolies that dominated the economic landscape. They aimed to promote greater control by the people over the economy, advocating for reforms that would curb corporate power.