The electronic configuration of $\mathrm{Cu}(\mathrm{II})$ is $3 \mathrm{~d}^9$ whereas that of $\mathrm{Cu}(\mathrm{I})$ is $3 \mathrm{~d}^{10}$. Which of the following is correct?

1. A $\mathrm{Cu}(\mathrm{II})$ is more stable Correct answer
2. B $\mathrm{Cu}$ (II) is less stable
3. C $\mathrm{Cu}(\mathrm{I})$ and $\mathrm{Cu}(\mathrm{II})$ are equally stable
4. D Stability of $\mathrm{Cu}(\mathrm{I})$ and $\mathrm{Cu}(\mathrm{II})$ depends on nature of copper salts