Liên minh công nông trí thức trong quá trình xây dựng xã hội chủ nghĩa ở việt nam

What does the ricardian theory state? a. countries should produce all goods and services if they canb. countries should not produce goods and services that minimize opportunity costsc. countries should import goods and services if they are cheaper in other countriesd. countries should export all goods and services if they make a profit