Which economic procedure best encourages voluntary exchange? government regulation scarcity price ceilings specialization (< my choice)

specialization (Option D)

From all the above options (i.e.  government regulation, scarcity, price ceilings,specialization) specialization is the economic procedure that boosts voluntary exchange the most. The reason is that in specialization, a country is not self-sufficient; it does not produce everything itself. It only produces those good or services, which it yields best in terms of price and efficiency and hence, since it is only producing limited products, it will have to depend on trade to obtain goods and services that other country, are producing better.

so they can see what that city is producing and to also see if they can some how get that product. like gold in africa.

a. $48.75

is the answer to your question