Hi, can you please help to explain the following question? Thx

(a) Explain the market failure argument against free trade and why it falls under the category of second best solution? (b) Why are international trade negotiations successful in reducing or eliminating tariff and non-tariff barriers among the nations of the world? Use the game theory approach to answer this question. (c) What is the interest parity condition and explain why it must hold if the foreign exchange market is in equilibrium