Hi there!
The correct answer is letter C) The United States promotes free trade to cause other nations to become less self-sufficient.
International trade is important to the American economy and to the economy of the world because neither the U.S. nor any other country has everything that its people need.
The foreign relations tradition is especially attentive to trade and commercial policy, territorial and maritime expansion, and the influence of economic considerations on U.S. foreign policy and grand strategy. The economic history subfield provides vital context on the growth of the U.S. economy.
So, as the U.S. promotes free trade because there were always be countries that need to import from their country.