Which point(s) are inefficient? Briefly explain why. A. Points \( \mathrm{W}, \mathrm{X}, \mathrm{Y} \), and V because they are unattainable. B. Points \( \mathrm{Z}, \mathrm{W}, \mathrm{X} \), and Y because they are attainable. C. Point V because it is unattainable. D. Point Z because production there is not using all available resources. E. Points \( \mathrm{W}, \mathrm{X} \), and Y because they are on the production possibilities frontier.

The correct answer is: **D. Point Z because production there is not using all available resources.** **Explanation:** - **Inefficient Points:** In the context of a Production Possibilities Frontier (PPF), points that lie **inside** the frontier represent inefficient use of resources because not all available resources are being utilized. - **Point Z:** According to option D, Point Z is producing at a level where not all resources are fully employed. This means that the economy could produce more of one or both goods without sacrificing the production of the other, indicating inefficiency. - **Other Options:** - **A & C:** Points that are unattainable (like V) are simply not feasible with the current resources and technology, but they are not considered inefficient because inefficiency pertains to achievable (attainable) points. - **B:** While some points might be attainable, not all attainable points are inefficient. Only those inside the PPF are inefficient. - **E:** Points on the PPF are efficient as they represent the maximum possible production levels with available resources. Therefore, **Point Z** is the inefficient point because it does not utilize all available resources effectively. **Answer:** **D. Point Z because production there is not using all available resources.**