A spring has a spring constant of $6.0\,\text{N cm}^{-1}$. It is connected to a second spring with spring constant $4.0\,\text{N cm}^{-1}$. An $80\,\text{N}$ load is hung from the composite spring. What extension does this composite spring produce?
- A$8.0\,\text{cm}$
- B$16\,\text{cm}$
- C$17\,\text{cm}$
- D$33\,\text{cm}$