If a Production Possibilities Frontier (PPF)is Concave Outward, It Follows

Multiple Choice

If a production possibilities frontier (PPF) is concave outward, it follows that

A) opportunity costs are constant between two goods.
B) the opportunity cost (of producing the good on the horizontal axis) rises as more of the good is produced.
C) the opportunity cost (of producing the good on the horizontal axis) falls as more of the good is produced.
D) the opportunity cost (of producing the good on the horizontal axis) first rises and then falls as more of the good is produced.