How does smith define "natural price"? how is "market price" different from "natural price"?

Smith says that occurs in all societies a natural regulation of rates of things for wages and goods, this is a price that is not too little nor too much regarding what is being paid considering the conditions of that society. While the market price is different as the price is regulated by the offer of the quantity of a product or service and the demand for it, the market price tends to vary in relationship to the natural price, being lesser, the same or more than it and competition can affect it a lot.

c or d both can be the answer

a. favoring native born americans over immigrants.