Consider a Graph of a Production Possibilities Curve

Consider a graph of a production possibilities curve. If a producer is operating at an inefficient point, then that producer:

A) cannot produce more of one good without giving up some of the other good.
B) can produce more of one good without producing less of the other good.
C) must be at an unattainable point on the production possibilities curve.
D) must be specializing in activities for which it has a comparative advantage.