Which of the following statements are true (assume there are only 2 goods in the economy)?

I. To realise the gains from trade, the more productive party should specialise in producing the more costly good and the less productive party should specialise in the other good.

II. Opportunity costs determine comparative advantages

III. Countries should produce goods in which the opportunity cost is higher

IV. Trade occurs when two countries have different comparative advantages.

Group of answer choices

a. only II and IV are true

b. only I, II, and III are true

c. only III and IV are true

d. only I and II are true