An applied force compresses a spring. The graph gives compressing force $F$ as a function of the spring length $L$. What is the spring constant for this spring?
- A$0.2\,\text{N m}^{-1}$
- B$5\,\text{N m}^{-1}$
- C$100\,\text{N m}^{-1}$
- D$200\,\text{N m}^{-1}$