question: The figure shows (a) and (b) two sections, (a) is a circle of rectangular holes, (b) a square u and v with circular holes are the spindle of the center. There are four answers about the moment of inertia L. and I, among which the correct is<image 1>
  Options: A: l(a)>1,(a);l(b)=l(b), B: l.(a) >L(a);l(b)>l,(b), C: l.(a) >2(a);l(b)>l,(b), D: l.(a) >L(a);l(b)>2,(b)