A conducting sphere of radius R is given a charge Q. The electric potential and the electric field at the centre of the sphere respectively are 

• A

  $\text{ zero and }\frac{Q}{4\pi {\epsilon }_0{R}^2}$

• B

  $\frac{Q}{4\pi {\epsilon }_{0}R}\text{ and zero }$

• C

  $\frac{Q}{4\pi {\epsilon }_{0}R}\text{ and }\frac{Q}{4\pi {\epsilon }_0{R}^2}$

• D

  Both are zero