If $\overline{\mathrm{p}},\overline{\mathrm{q}}\text{ and }\overline{\mathrm{r}}$ are three unit vectors represented by the three sides of an equilateral triangle such that $\overline{\mathrm{p}}\cdot \overline{\mathrm{q}}+\overline{\mathrm{q}}.\overline{\mathrm{r}}=0$, then which of the following is the correct relation between the three vectors? 

• A

  $\left|\overline{\mathrm{p}}\right|+\left|\overline{\mathrm{q}}\right|=\left|\overline{\mathrm{r}}\right|$

• B

  $\overline{\mathrm{q}}+\overline{\mathrm{r}}=\overline{\mathrm{p}}$

• C

  $\overline{\mathrm{r}}+\overline{\mathrm{p}}=\overline{\mathrm{q}}$

• D

  $\overline{\mathrm{p}}+\overline{\mathrm{q}}\text{ + }\overline{\mathrm{r}}=0$