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

• A

  $\overrightarrow{\mathrm{r}} \cdot \overrightarrow{\mathrm{T}}=0$ and $\overrightarrow{\mathrm{F}} . \overrightarrow{\mathrm{T}} \neq 0$
• B

  $\overrightarrow{\mathrm{r}} \cdot \overrightarrow{\mathrm{T}} \neq 0$ and $\overrightarrow{\mathrm{F}} \cdot \overrightarrow{\mathrm{T}}=0$
• C

  $\overrightarrow{\mathrm{r}} \cdot \overrightarrow{\mathrm{T}} \neq 0$ and $\overrightarrow{\mathrm{F}} \cdot \overrightarrow{\mathrm{T}} \neq 0$
• Correct answer
  D

  $\overrightarrow{\mathrm{r}} \cdot \overrightarrow{\mathrm{T}}=0$ and $\overrightarrow{\mathrm{F}} \cdot \overrightarrow{\mathrm{T}}=0$

Hence, the correct answer is option: 'D'.