The M.I about an axis of symmetry is given by (mass x sum of square of perpendicular semi axis) x  1 /n .

then

(a)if n=3 , body is rectangular

(b)if n=4,body is elliptical

(c)if n=5 body is spherical

(d)all of the above

'sum of square of perpendicular semi axis'-what does this mean?

it is a sphere

the axis of symmetry passes through its center

MI about that axis is 2/5MR²

 (mass x sum of square of perpendicular semi axis) x  1 /n= M x( R²+R²) x1/5= 2/5MR²

the ans is (d)

pols someone provide a better soln

If n=3,then I=m[(a/2)²+(b/2)²](1/3)=m(a²+b²)/12 where a,b are length and breadth.Hence,it is correct.

If n=4,then I=m[a²+b²](1/4) where a,b are semi-major and semi-minor axes.Hence,It is also correct.

For n=5,the ans given by prathab is right.So,all are correct.