The Reason That the Production Possibilities Frontier Is Usually a Bow-Shaped

Multiple Choice

The reason that the production possibilities frontier is usually a bow-shaped curve instead of a straight line is that:

A) a curve makes it easier to illustrate the concepts of scarcity and prices than a straight line.
B) early economists began drawing them in this way and the convention has continued throughout the years.
C) output eventually reaches a maximum and then declines.
D) resources are not perfectly adaptable to the production of all goods.
E) the frontier will shift outward over time.