Which of the following represents frictional unemployment?

I. The demand for refrigerators falls when the economy enters a recession and refrigerator manufacturers lay off some of their workers.
II. General Motors decides to close its U.S. factories and relocate its car-manufacturing division to Mexico.
III. After quitting your job in Ohio to be closer to your family in California, you are now looking for a new job.
IV. Carla's boss recently fired her for doing poor work and she hasn't yet found a new job.