Which of these are natural result of specialization

I had a question like this various Economics classes, as part of producer theory, trade, and overall economic growth. So I hope this translates to History as well. The answer is C) Specialization leads to interdependence. Why? If a country (or region, or industry) specializes in producing one thing, they will need to trade in order to get the other things they need. A and D both go against this logic and are wrong. Specialization means picking something you are good at (producing at a lower price than others), and using all your resources for it. B is probably wrong because it just seems silly. Not everyone will get rich. That's also part of Economics - there are ups and downs in the economy, there will always be some unemployment, etc.