The graph illustrates the effect on a spring of a force applied, with the force increasing to a maximum of $5.0\,\text{N}$. The spring follows Hooke’s law for forces up to $7.0\,\text{N}$. What total extension does the spring produce when a force of $7.0\,\text{N}$ is applied?
- A$4.2\,\text{cm}$
- B$5.6\,\text{cm}$
- C$15\,\text{cm}$
- D$20\,\text{cm}$