If the Chinese economy could create all goods with fewer resources per unit than are needed in US, the citizens of China would: (i) Encompass a comparative advantage in the whole thing. (ii) Be self-sufficient since there would be no potential profits from trade. (iii) Not trade at all with people in United States. (iv) Still profit by specializing and exchanging some of its output in which China enjoyed the comparative advantage for goods generated with comparative advantages through Americans.
What is the right answer?