The diagram shows a spanner being used to tighten a nut. A force $F$ acts at right-angles to the spanner at a point $0.25\,\text{m}$ from the centre of the nut. Once the nut has been tightened completely, the applied force is $200\,\text{N}$. What is the resistive torque, in an anticlockwise direction, that stops any further tightening?
- A$8\,\text{N m}$
- B$42\,\text{N m}$
- C$50\,\text{N m}$
- D$1250\,\text{N m}$