If $\mathrm{p}$ is the $\mathrm{AM}$ of $\mathrm{q}$ and $\mathrm{r}$ and $\mathrm{q}$ is the $\mathrm{GM}$ of $\mathrm{r}$ and $\mathrm{p}$, then $\mathrm{HM}$ between $\mathrm{p}$ and $\mathrm{q}$ is
(a) $\mathrm{p}^{2}$
(b) $\mathrm{pq}-\mathrm{r}$
(c) $\mathrm{r}$
(d) $\mathrm{pq}+\mathrm{r}$