Consider a particle of mass $m$ having linear momentum $\vec{p}$ at position $\bar{r}$ relative to the origin $O$. Let $\vec{L}$ be the angular momentum of the particle with respect to the origin. Which of the following equations correctly relate(s) $\vec{r}, \vec{p}$ and $\vec{L} ?$
(a) $\frac{d \vec{L}}{d t}+\vec{r} \times \frac{d \vec{p}}{d t}=0$
(b) $\frac{d \vec{L}}{d t}+\frac{d \bar{r}}{d t} \times \vec{p}=0$
(c) $\frac{d \vec{L}}{d t}-\frac{d \vec{r}}{d t} \times \vec{p}=0$
(d) $\frac{d \vec{L}}{d t}-\vec{r} \times \frac{d p}{d t}=0$