Concept:A production possibility curve shows the maximum combinations of two goods an economy can produce with available resources and technology.Explanation:The curve emphasizes scarcity because it shows limited productive capacity.Points inside the curve show unemployment of labour and inefficient use of resources.Points on the curve show efficient use of resources.The curve is drawn for a given level of resources and technology at a particular time.Therefore, it does not show changes such as economic development, which involves growth over time.Answer: D. Economic development