Answer:
The correct answer is: a new law that interferes with economic efficiency.
Step-by-step explanation:
A production possibilities frontier shows all the points where production is efficient. The resources are being completely employed. The points above the frontier are unattainable. The points below the frontier are attainable but inefficient.
If there is a movement from the frontier to a point below it. This means inefficient allocation of resources. It can happen because of some law interfering in efficient allocation of resources.