A metal wire has one end secured to a fixed point, while a load is suspended from the opposite end so that the wire hangs straight down. The load is then raised from zero to $20\,\text{N}$. As a result, the wire undergoes an elastic extension of $5.0\,\text{mm}$. Next, the load is lowered to $12\,\text{N}$, and the extension falls to $3.0\,\text{mm}$. How much strain energy is released as the wire is unloaded?
- A$0.8 \times 10^{-2}\,\text{J}$
- B$1.8 \times 10^{-2}\,\text{J}$
- C$2.4 \times 10^{-2}\,\text{J}$
- D$3.2 \times 10^{-2}\,\text{J}$