A Decrease in the Unemployment Rate from 21 Percent to 17

A decrease in the unemployment rate from 21 percent to 17 percent can be illustrated as:

A) ​an inward shift of the production possibilities curve.
B) ​an outward shift of the production possibilities curve.
C) ​a movement down and to the right along the production possibilities curve.
D) ​a movement from a point inside the production possibilities curve to a point closer to the production possibilities curve.