For the same mass which of the following will have the largest moment of inertia about an axis passing through the centre of gravity and perpendicular to the plane of the body?
MI of disk of radius a, about given axis is ma22
MI of the ring of radius a about given axis is ma2
MI of square of side a about given axis is ma26=ma26
MI of four rods forming a square of side a about given axis
4×m(a)212+ma2=4ma23
So, among all options four rods forming square of side a has highest moment of inertia.
Thus option D is correct.