What is the main inference that can be drawn from adam smith book the wealth of nations

The correct answer is C: A free-market economy works well only without the government’s interference.

The main inference that can be drawn from 'The Wealth of the Nations' (1776) is a strong defense of free markets, with no state interventions.

Adam Smith (1723-1790) believed that the interactions ocurring in the markets, where many economic agents gathered pursuing their individual interests, led to agreements which generated positive outcomes for all participants and in turn, for the society as a whole. In such situations, when the leaving the markets alone, the invisible hand of the markets operated,  bringing wealth for everybody.

Accordingly, he advised goverments to adopt a policy of laissez-faire with no interventions.