If Nations Such as Germany,Japan,and Canada Prohibited International Trade in Automobiles,what

If nations such as Germany,Japan,and Canada prohibited international trade in automobiles,what would a likely effect be

A) The price effect would become a more significant consideration for each firm that makes automobiles.
B) The excess of price over marginal cost would become less pronounced in the automobile market.
C) All countries would become better off because all automakers would be earning higher profits.
D) The competition would increase within each country, which would keep prices closer to marginal cost.