A ruler with length $0.30\,\text{m}$ is balanced about a pivot at its midpoint. Two forces, each of magnitude $2.0\,\text{N}$, act in opposite directions at the ends of the ruler so that they form a couple as illustrated. In the position shown, what is the size of the torque of the couple on the ruler?
- A$0.23\,\text{N m}$
- B$0.39\,\text{N m}$
- C$0.46\,\text{N m}$
- D$0.60\,\text{N m}$