An insulating solid sphere of radius 'R' is charged in a non uniform manner such that volume charge density $\mathrm{\rho }=\frac{\mathrm{A}}{\mathrm{r}}$ where A is a positive constant and r the distance from centre. Electric field strength at any inside point at distance ${\mathrm{r}}_1$ is: 

• A

  $\frac{1}{4{\mathrm{\pi e}}_0}\frac{4\mathrm{\pi A}}{{\mathrm{r}}_1}$

• B

  $\frac{1}{4{\mathrm{\pi e}}_0}\frac{\mathrm{A}}{{\mathrm{r}}_1}$

• C

  $\frac{\mathrm{A}}{{\mathrm{\pi e}}_0}$

• D

  $\frac{\mathrm{A}}{2{\mathrm{e}}_0}$