From A conducting sphere of radius R a cavity of radius R/2 is cut out as shown in the figure. At the centre of cavity a point charge q is placed then, the potential and field at point P as shown in the figure is

• A

  $V=\frac{q}{2\pi {\epsilon }_{0}d},E=\frac{q}{2\pi {\epsilon }_0{d}^2}$

• B

  $V=\frac{q}{4\pi {\epsilon }_{0}d},E=\frac{q}{2\pi {\epsilon }_0{d}^2}$

• C

  $V=\frac{q}{4\pi {\epsilon }_{0}d},E=\frac{q}{4\pi {\epsilon }_0{d}^2}$

• D

  $V=\frac{q}{2\pi {\epsilon }_{0}d},E=\frac{q}{4\pi {\epsilon }_0{d}^2}$