When a Nation First Begins to Trade with Other Countries

When a nation first begins to trade with other countries and the nation becomes an exporter of soybeans,

A) this is an indication that the world price of soybeans exceeds the nation's domestic price of soybeans in the absence of trade.
B) this is an indication that the nation has a comparative advantage in producing soybeans.
C) the nation's consumers of soybeans become worse off and the nation's producers of soybeans become better off.
D) All of the above are correct.