There is a shell of mass $\mathrm{M}$ and density of the shell is uniform. The work done to take a point mass from point $\mathrm{A}$ to $\mathrm{B}$ is $[\mathrm{AB}=\mathrm{r}]$

• A

  $\frac{\mathrm{GmM}}{\mathrm{r}}$
• B

  $\frac{\mathrm{GmM}}{\mathrm{R}}$
• C

  $-\frac{\mathrm{GmM}}{\mathrm{r}}$
• Correct answer
  D

  zero

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