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

1. A
   $\vec{r}\cdot \vec{\tau }=0$ and $\vec{F}\cdot \vec{\tau }\ne 0$
2. B
   $\vec{r}\cdot \vec{\tau }\ne 0$ and $\vec{F}\cdot \vec{\tau }=0$
3. C
   $\vec{r}\cdot \vec{\tau }\ne 0$ and $\vec{F}\cdot \vec{\tau }\ne 0$
4. D
   $\vec{r}\cdot \vec{\tau }=0$ and $\vec{F}\cdot \vec{\tau }=0$