Answer
We can rank the disks according to the rotational inertia about the disk center:
$1 = 3 \gt 2$
Work Step by Step
Disk 1 and Disk 3 are identical so they have the same rotational inertia.
Disk 2 has more mass closer to the center and less mass farther from the center. Therefore, Disk 2 has a smaller rotational inertia.
We can rank the disks according to the rotational inertia about the disk center:
$1 = 3 \gt 2$
