For a spherical Gaussian surface of radius $r$ centered on a point charge $Q$, which expression follows from Gauss's law for the electric field magnitude?

$E=\frac{Q}{4\pi r{\epsilon }_0}$

$E=\frac{Q{r}^2}{4\pi {\epsilon }_0}$

$E=\frac{Q}{4\pi {\epsilon }_0{r}^2}$

$E=\frac{4\pi {\epsilon }_{0}Q}{r^2}$