Two unequal masses mm and 2m are attached to a thin bar of negligible mass that rotates about an axis perpendicular to the bar. when mm is a distance 2d from the axis and 2m is a distance dd from the axis, the moment of inertia of this combination is i. if the masses are now interchanged, the moment of inertia will be

(a) 2/3 i,
(b) i ,
(c)3/2 i ,
(d) 2 i ,
(e) 4 i