Which of the following is a correct statement about production possibilities frontiers?

A、Aneconomycanproduceonlyontheproductionpossibilitiesfrontier.;
B、Aneconomycanproduceatanypointinsideoroutsideaproductionpossibilitiesfrontier.;
C、Aneconomycanproduceatanypointonorinsidetheproductionpossibilitiesfrontier,butnotoutsidethefrontier.;
D、Aneconomycanproduceatanypointinsidetheproductionpossibilitiesfrontier,butnotonoroutsidethefrontier.