What is the main idea of paragraph 3? A. What American factories offered their farmer119/187What is the main idea of paragraph 3?What American factories offered their farmerWhat led American farmers to leaving their farmsHow much capital was needed in American factoriesHow the American work force benefited from new techologiesGiải thíchÝ chính của đoạn 3 là: Cần bao nhiêu vốn trong các nhà máy của Mỹ.Chọn C