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:

Question

( A ) Both are zero
( B ) $\frac{Q}{4 \pi \varepsilon_0 R}$ and Zero
( C ) $\frac{Q}{4 \pi \varepsilon_0 R}$ and $\frac{Q}{4 \pi \varepsilon_0 R^2}$
( D ) Zero and $\frac{Q}{4 \pi \varepsilon_0 R^2}$