Which of these is not a good Argument in favor of democracy? Why?

From above given four statements first three totally talks in the favor of democracy but “Democracies are more prosperous than others”, this argument is not in favor of democracy. As in any democratic country there are both rich and poor kinds of people and all of them play equal role in formation of any government. The representatives that are chosen by the people make decisions according to the welfare of the public and due to the fear of losing election they work hard. The prosperity of the country is dependent on various other factors like availability of natural resources, financial history, demographic and manpower constraints, so prosperity is not an argument that can be made in the favor of a democratic country in general.

Hence, option (D) is correct