C, positive self-talk
If you tell yourself you can do something, you will.
Countries would be able to increase their productivity for the services with comparative advantage. A country then can sell products they produce efficiently and also would buy from other nations the products that they cannot produce. The comparative advantage can lose if there are competitors operating in a low wage country.
B. Real wages
Real wages show the value of wages adjusted for inflation. Real wages are a guide to how living standards have changed.
