Along a Concave Production Possibility Frontier,the Per-Unit Opportunity Cost of Increasing

Multiple Choice

Along a concave production possibility frontier,the per-unit opportunity cost of increasing output typically:

A) increasing because specializing in the production of just one good is irrational.
B) decreasing because resources are difficult to move from one sector to another.
C) increasing because some resources are better-suited to producing one good than to the other.
D) decreasing because resource productivity increases naturally over time.