Which of the following statements regarding transition elements is/are incorrect?

Question

(1) $Cu^{2+}(3d^{10})$ is more stable than $Cu(I)$ though $Cu(I)$ has a $3d^{10}$ electronic-configuration

(2) $Cu^{2+}(3d^{10})$ is less stable than $Cu(I)$ because $Cu(I)$ has a $3d^{10}$ electronic-configuration (3) A 4s sub-shell is filled prior to 3d but on ionization, 4s electrons are removed (4) A 4s sub-shell is not filled prior to 3d and on ionization, 4s electrons are removed

$\begin{array}{1 1} Cu \\ Zn \\ Sc \\ Mn\end{array}$