A cable in a suspension bridge carries a load of $19.3 \times 10^5\,\text{N}$. Under this load, the cable extends by $47\,\text{mm}$. When a lorry then travels across the bridge, the force on the cable rises to $23.3 \times 10^5\,\text{N}$. The force-extension graph for the cable is shown. What is the increase in strain energy in the cable when the lorry is crossing the bridge?
- A$21\,\text{kJ}$
- B$23\,\text{kJ}$
- C$45\,\text{kJ}$
- D$66\,\text{kJ}$