A solid sphere of mass $M$, radius $R$ and having moment of inertia about an axis passing through the centre of mass as $I$, is recast into a disc of thickness $t$, whose moment of inertia about an axis passing through its edge and perpendicular to its plane remains $I$. Then, radius of the disc will be

• Correct answer
  A

  $\frac{2 R}{\sqrt{15}}$
• B

  $R \sqrt{\frac{2}{15}}$
• C

  $\frac{4 R}{\sqrt{15}}$
• D

  $\frac{R}{4}$

Hence, the correct answer is option: 'A'.