The Stolper-Samuelson theorem states that: A) free international trade increases the real income of the nation's relatively scarce factor and the nation's relatively abundant factor. B) free international trade increases the real income of the nation's relatively scarce factor and reduces the real income of the nation's relatively abundant factor. C)free international trade reduces the real income of the nation's relatively scarce factor and increases the real income of the nation's relatively abundant factor. D)free international trade does not change the real income of the nation's relatively abundant factor and increases the real income of the nation's relatively scarce factor.