Which of the Following Statements Is True

Which of the following statements is true?

A) If the opportunity costs differ between two countries, there is no opportunity for mutually advantageous trade.
B) International trade leads countries to specialize in the production of those goods for which they have an absolute, rather than a comparative, advantage.
C) Free international trade can increase the availability of all goods and services in the countries that participate in trade.
D) The potential costs of free trade generally outweigh the benefits.