All $Cu(II)$ halides are known,except the iodide. The reason for this is that:

• A
  $Cu^{2+}$ oxidises iodide to iodine
• B
  $Cu^{2+}$ has much more negative hydration enthalpy
• C
  $Cu^{2+}$ ion has smaller size
• D
  iodide is a bulky ion