Final answer:
Option C is correct; the 1920s saw a decline in agricultural production and farm incomes due to overproduction, low commodity prices, and lack of effective government support after the post-World War I demand dropped.
Step-by-step explanation:
The statement that accurately characterizes American Agriculture during the 1920s is C. Decline in agricultural production and farm incomes. After World War I, farmers faced severe difficulties due to a number of factors. Initially, they experienced prosperity with high demand and prices for their products during the war. As the war ended, demand decreased, and prices plummeted. Overproduction in hopes of compensating for falling prices further exacerbated the situation, leading to a surplus that further depressed prices. The U.S. government, under President Coolidge, consistently vetoed federal price supports which could have helped stabilize the market. This all culminated in widespread economic hardship for farmers, leading to loan defaults and bank failures. Overproduction, low prices, and lack of government support characterized the grim reality of American agriculture during this decade.