Answer: А. A country joins a partnership to expand international trade.
Step-by-step explanation:
Liberal foreign policy is one that sees a country try to spread the ideals of liberalism such as free and fair elections, individual and civil liberties and the free market and economy.
They can do this either militarily or through International organizations and partnerships that push a certain agenda. A country joining a partnership to expand international trade is therefore an example of a liberal foreign policy because it involves spreading the liberal idea of free trade.