The graph illustrates how the extension of a spring changes as the applied force varies. If no force acts on the spring, its length is $1.0\,\text{cm}$. What increase occurs in the strain energy stored in the spring when its length rises from $2.0\,\text{cm}$ to $3.0\,\text{cm}$?
- A$0.020\,\text{J}$
- B$0.030\,\text{J}$
- C$0.040\,\text{J}$
- D$0.050\,\text{J}$