Calculate the moment of inertia of an annular disc about an axis tangent to the outer circle and lying in the plane of the disc. The mass of the disc is $M$,the inner radius is $R_1$,and the outer radius is $R_2$.

• A
  $I_{AB} = M(R_1^2 + R_2^2) + MR_2^2$
• B
  $I_{AB} = \frac{M}{4}(R_1^2 - R_2^2) + MR_2^2$
• C
  $I_{AB} = \frac{M}{4}(R_1^2 + R_2^2) + MR_2^2$
• D
  $I_{AB} = \frac{M}{4}(R_1^2 - R_2^2) - MR_2^2$