If two 2nC point charges are located at (1, 0, 0) and (-1, 0, 0) in free space. The relation of \(\left| {\frac{{dV}}{{dz}}} \right|\)on the z-axis will be
1
\(\frac{{108z}}{{{{\left( {{z^2} + 1} \right)}^{\frac{3}{2}}}}}\)
2
\(\frac{{36z}}{{{{\left( {{z^2} + 1} \right)}^{\frac{3}{2}}}}}\)
3
\(\frac{{18z}}{{{{\left( {{z^2} + 1} \right)}^{\frac{3}{2}}}}}\)
4
\(\frac{{12z}}{{{{\left( {{z^2} + 1} \right)}^{\frac{3}{2}}}}}\)