What component of a computer system holds the operating system when the computer is not running

The same thing that holds the operating system when the computer is running.

It is usually a Hard Drive (HDD) or a Solid State Drive (SDD). I would recommend storing the operating system on the SSD because it loads faster, but a lot of computer's don't have SSD's which is why they are stored on Hard Drive's.

It would be 10 inches

If ana decided to be against in prioritizing the task in her to do list, she will likely have insufficient time in doing the things in which she wouldn't be able to finish and in the same way, she won't be able to finish all of the task that she needed to do.