Answer: d.Move us along the perimeter of the PPC
Explanation:
The Production Possibilities Curve (PPC) is used to demonstrate the concept of scarcity and trade-offs by showing different combinations of output of two goods give certain resources.
As the goods use the same resources, increasing the output of one good reduces the output of the other. The PPC therefore shows the optimal level of resource utilization. If production is efficient, it will follow this optimal level by moving along the perimeter of the PPC.