Which of the Following Would Be Considered Frictional Unemployment? I

Which of the following would be considered frictional unemployment? I. Alisha has taken a job at a different company in order to accept a promotion. She quit her current job but has one month off until she starts her new job.
II) John has lost his job as a book binder as the demand for e-books has replaced demand for traditional books in the country.
III) Melissa quit her full-time job to become a full-time student in order to pursue her Ph.D.

A) I only
B) II only
C) I and II only
D) III only