Unless There Are Barriers to Prevent Free International Trade,a Country

Unless there are barriers to prevent free international trade,a country becomes an importer:

A) when the world price exceeds the domestic price.
B) when the domestic price exceeds the world price.
C) when there is an excess supply in the domestic market.
D) when it wants to expand its scale of operation.
E) when the opportunity cost of producing a good is lower relative to other countries.