Imagine an electron moving in the potential field of a proton given by $\text{V}={\text{V}}_0\text{ ln}\frac{\text{r}}{{\text{r}}_0}$ where $r_0$ is a positive constant and $r$ is the distance between the electron and proton. Assuming Bohr's model to be applicable, the variation of $r_n$ with $n$ (principal quantum number) is