Variable Density Rotational Inertia

The mass density of a solid cylinder of radius R and height h is a function of the radial distance r from its central axis, given by $\rho(r) = \rho_0 \frac{r}{R}$, where $\rho_0$ is a constant. Which of the following gives the rotational inertia of the cylinder about its central axis in terms of its total mass M?