If F is the force acting on a particle having position vector r and...

Options

1. A$\vec{r} \cdot \vec{\tau}=0$ and $\vec{F} \cdot \vec{\tau} \neq 0$
2. B$\overrightarrow{\mathrm{r}} \cdot \vec{\tau} \neq 0$ and $\vec{F} \cdot \vec{\tau}=0$
3. C$\vec{r} \cdot \vec{\tau}>0$ and $\vec{F} \cdot \vec{\tau} < 0$
4. D$\overrightarrow{\mathrm{r}} \cdot \vec{\tau}=0$ and $\vec{F} \cdot \vec{\tau}=0$