Concept:The outward-bowed shape of the Production Possibility Curve (PPC) reflects the law of increasing marginal cost.
Explanation:The PPC shows the maximum combinations of two goods an economy can produce with full and efficient use of available resources.
As more of one good is produced, resources that are less suited to that good must be transferred from the other good.
This leads to rising opportunity costs because each additional unit of the good costs more of the other good to produce.
Therefore, the curve bends outward (is concave to the origin) instead of being a straight line.
The slope of the PPC becomes steeper as output increases, illustrating increasing marginal cost.
Points inside the curve show inefficiency, while points outside are unattainable, but neither explains the bowed shape.
Answer:D. the law of increasing marginal cost.