The gravitational field due to a mass distribution is given by \(E =\frac{k}{x^3}\hat{i}\). Then the magnitude of gravitational potential at a distance 'd' along the x axis is-
1
\(\frac{k}{2d}\)
2
\(\frac{k}{2d^2}\)
3
\(-\frac{k}{2d^2}\)
4
\(-\frac{k}{2d}\)