Find the odd one out:

Question

$\begin{array}{1 1} (a)\text{ Neutral Salt:NaCl}\\ \text{(b) Acid Salt:$CuSO_4,5H_2O$} \\ \text{ (c) Basic Salt:$CuSO_4,5H_2O$} \\ \text{(d) Nonhydrated Salt:$KNO_3$} \end{array}$