Production Possibilities Frontiers in the Ricardian Model

Multiple Choice

Production possibilities frontiers in the Ricardian model:

A) are linear (i.e., straight lines) , with end points showing a country's production when it produces only one or the other good.
B) are bowed out from the origin, with end points showing a country's production when it produces only one or the other good.
C) are linear and begin from the origin.
D) are curvilinear and increase at a decreasing rate.