The Difference Between a Straight-Line Production Possibilities Frontier and One

Multiple Choice

The difference between a straight-line production possibilities frontier and one that is concave is that:

A) the concave production possibilities frontier exhibits constant opportunity costs, while the straight line frontier does not.
B) the concave frontier reflects the problem of scarcity but the straight line frontier does not.
C) the straight line frontier reflects constant opportunity costs but the concave frontier does not.
D) neither the straight line nor the concave frontier reflect output limits.