Final answer:
California has the highest percentage of its inmate population serving sentences in jails rather than prisons.
Step-by-step explanation:
The state with the highest percentage of its inmate population serving sentences in jails rather than prisons is California (option b).
According to the information provided, the United States has the highest incarceration rate in the world, and about one-in-four imprisoned persons are in American jails.
While the exact percentage for each state is not specified, it is clear that California has a significant number of inmates in its jails.
This information highlights the issue of mass incarceration and the challenges faced by the criminal justice system in the United States.