The radial wavefunction of hydrogen atom with the principal quantum number n = 2 and the orbital quantum number l = 0 is \(R_{20}=N\left(1-\frac{r}{2 a}\right) e^{-\frac{r}{2 a}}\)  where N is the normalization constant. The best schematic representation of the probability density P(r) for the electron to be between r and r + dr is