A rod that is not uniform has a mass of $100\,\text{g}$ and a length of $50\,\text{cm}$. A chain supports it at its midpoint. Equilibrium is maintained by suspending a mass of $60\,\text{g}$ from the right-hand end, as shown. The centre of gravity of the rod is at a distance $d$ from its left-hand end. What is the value of $d$?
- A$10\,\text{cm}$
- B$15\,\text{cm}$
- C$25\,\text{cm}$
- D$40\,\text{cm}$