Wire is bent in a circle of radius $10\;cm$ It is given a change on it uniformly. What is the electric potential at the center ?

Question

$\begin{array}{1 1} 2.25 \times 10^7\;V \\ 22.5 \times 10^7\;V \\ 2.25 \times 10^6\;V \\ 0.225 \times 10^6 \;V \end{array} $