In David Ricardo's theory of comparative advantage,
A.
international trade is a zero-sum game in which one trading partner's gain comes at the expense of another's loss.
B.
liberalization of international trade will enhance the welfare of the world's citizens.
C.
is a short-run argument, not a long-run argument.
D.
both answers a and b are correct. has been superseded by the now-orthodox view of mercantilism.