One power state will shut apps and files, log off users, and save the kernel state and system session to a hibernation file before shutting down. When the computer is rebooted, it will restore that file immediately and rapidly, saving some of the time involved in a normal boot. This is the description of which states?

Fast Startup works similarly to Hibernate, except, instead of preserving all of your programs and data as they were so that you can return to work immediately, it stores the system state. Fast Startup, as indicated in the question, will stop running apps and log off any users before saving the contents of RAM to a hibernation file. When the computer restarts, it reads the hibernation file and loads drivers, system state, and the kernel considerably faster than if the system had to read all of that back into RAM individually, as it would in a regular cold boot. Sleep saves everything that is open in RAM and switches to a low-power mode. The display and drives do not consume power, but memory must be refreshed regularly in order to retain information. Sleep consumes extremely little power but "wakes up" very rapidly with everything still open. Hibernate retains open programs and data to the hard drive and, once hibernated, consumes no power, although it does not resume its state as rapidly as Sleep.