A Nation's Comparative Advantage in the Production of an Item

A nation's comparative advantage in the production of an item is determined by

A) which country has already specialized in production of the item.
B) the total and marginal costs of producing the item.
C) the opportunity cost of producing the item relative to a trading partner's opportunity cost of producing the same item.
D) specialization in the production of all goods.
E) the quantity of resources required to produce a unit of the item.