Assume a Bowed-Out Shape of a Production Possibilities Frontier Showing

Assume a bowed-out shape of a production possibilities frontier showing possible output levels of good A and good B.What is indicated if the economy produces more and more of good B?  

A)  that larger and larger amounts of good A must be sacrificed 
B)  that smaller and smaller amounts of good A must be sacrificed 
C)  that more of good A will be produced 
D)  that the amount of resources available in the economy must be increased