A stress-strain graph for a metal is provided. What is the strain energy per unit volume of a rod made from this metal when the rod’s strain is $0.010$?
- A$10\,\text{kJ m}^{-3}$
- B$100\,\text{kJ m}^{-3}$
- C$1.0\,\text{MJ m}^{-3}$
- D$10\,\text{MJ m}^{-3}$