The Quantity of Shoes Produced Is Measured Along the Horizontal

Multiple Choice

The quantity of shoes produced is measured along the horizontal axis of a PPF and the quantity of shirts is measured along the vertical axis. As you move down toward the right along the PPF, the marginal cost of

A) shoes decreases.
B) shoes increases.
C) shirts increases.
D) shoes and shirts is equal at the midpoint between the vertical and horizontal axis.