A body rolls without slipping. The radius of gyration of the body about an axis passing through its centre of mass is $k$. If radius of the body be $R$, then the fraction of total energy associated with its rotational energy will be
(a) $\left(k^{2}+R^{2}\right)$
(b) $\left(k^{2} / R^{2}\right)$
(c) $\left[k^{2} /\left(k^{2}+R^{2}\right)\right]$
(d) $\left[R^{2} /\left(k^{2}+R^{2}\right)\right]$