What Is Shown by the Production Possibility Frontier Model

What is shown by the production possibility frontier model?

A) That if consumers decide to buy more of a product, its price will increase.
B) That a market economy is more efficient in producing goods and services than is a centrally planned economy.
C) That economic growth can only be achieved by free market economies.
D) That if all resources and current technology are fully and efficiently utilised, more of one good can be produced only by producing less of another good.