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

• A
  $Cu(II)$ is less stable
• B
  Stability of $Cu(I)$ and $Cu(II)$ depends on the nature of copper salts
• C
  $Cu(II)$ is more stable
• D
  $Cu(I)$ and $Cu(II)$ are equally stable