Let $\overrightarrow{F}$ be the force acting on a particle having position vector $\overrightarrow{r}$ and $\overrightarrow{\tau}$ be the torque of this force about the origin. Then :

Question

( A ) $\overrightarrow{r}. \overrightarrow{\tau} = 0$ and $\overrightarrow{F}. \overrightarrow{\tau} = 0$
( B ) $\overrightarrow{r}. \overrightarrow{\tau} \neq 0$ and $\overrightarrow{F}. \overrightarrow{\tau} \neq 0$
( C ) $\overrightarrow{r}. \overrightarrow{\tau} \neq 0$ and $\overrightarrow{F}. \overrightarrow{\tau} = 0$
( D ) $\overrightarrow{r}. \overrightarrow{\tau} = 0$ and $\overrightarrow{F}. \overrightarrow{\tau} \neq 0$