Mutually Beneficial International Trade Between Two Countries Depends on

Mutually beneficial international trade between two countries depends on

A) each country having an absolute advantage in the production of a different good
B) one country being worse (requiring more resources) than the other in the production of every good
C) at least one country having a zero opportunity cost in the production of at least one good
D) one country being relatively better at producing a good (which makes the other country relatively worse at it)
E) one country being relatively better at producing all goods