$\mathrm{P}$ is the probability of finding the $1\mathrm{s}$ electron of the hydrogen atom in a spherical shell of infinitesimal thickness, $\mathrm{dr}$, at a distance, $\mathrm{r}$, from the nucleus. The volume of this shell is $4\mathrm{\pi }{\mathrm{r}}^2\mathrm{d}\mathrm{r}$. The qualitative sketch of the dependence of $\mathrm{P}$ on $\mathrm{r}$ is: