4. (a) Suppose the US can produce everything it needs cheaper than any other country, therefore it gets no benefit by trading with any other country. Evaluate this statement. (b) When an exchange between two parties is voluntary and based on self-interest, can one party be better off and the other worse off? Why or why not? (c) Suppose a country produces both- a high quality and also a low quality of good. When it exports both types of good to another country: Will it export more of high quality good or low quality good? Why or why not?