The graph illustrates the effect of a force of up to $5\,\text{N}$ being applied to a spring. Assuming the spring follows Hooke’s law, what is the total extension caused by a $7\,\text{N}$ force?
- A$4.2\,\text{cm}$
- B$5.6\,\text{cm}$
- C$15.2\,\text{cm}$
- D$19.6\,\text{cm}$