B. the North and South. black people started moving from the rural south to the industrialnirth
Answer: See explanation
Explanation:
Voluntary exchange is simply referred to as an act whereby both the buyers and the sellers can engage in transactions in the market freely.
Voluntary exchange is a fundamental assumption made by neoclassical economics which forms the basis of contemporary mainstream economics.
According to the principle, people act based on their interest. In a scenario whereby the individuals believe that they will not gain from a particular transaction, they won't engage in such.
