Answer:
III. Points on the PPF curve are the only ones that achieve "productive efficiency"
Explanation:
What is true about productive efficiency is that Points on the PPF curve are the only ones that achieve "productive efficiency".
Productive efficiency is an economic term that is concerned with producing goods and services with the optimal combination of inputs to produce maximum output for the minimum cost.
For it to be said that an economy is productively efficient means the economy must be producing on its production possibility frontier
Hence productive efficiency happens when production is reportedly occurring along a production possibility frontier (PPF).