A solid sphere of mass $\mathrm{M}$ and radius $\mathrm{R}$ is divided into two unequal parts. The first part has a mass of $\frac{7\mathrm{M}}{8}$ and is converted into uniform disc of radius $2\mathrm{R}$ . The second part is converted into a uniform solid sphere. Let ${\mathrm{I}}_1$ be the moment of inertia of the disc about its axis and ${\mathrm{I}}_2$ be the moment of inertia of the new sphere about its axis. The ratio ${\mathrm{I}}_1/{\mathrm{I}}_2$ is given by:

• Correct answer
  A

  $140$
• B

  $185$
• C

  $65$
• D

  $285$

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