Which of the following statements are correct about Zn, Cd and Hg ?...

(A) $Zn, Cd$ and $Hg$ have low values of enthalpies of atomization. These metals have relatively weak metallic bonding due to their filled or nearly filled d-orbitals. In these metals, the valence electrons are not as delocalized as in other transition metals because the d-orbitals are filled or nearly filled. This leads to weaker metallic bonding, resulting in lower enthalpies compared to transition metals with partially filled d-orbitals. Thus statement (A) is incorrect.
(B) $Zn$ and $Cd$ shows $+ 2$ oxidation state whereas $Hg$ shows $+ 1$ and $+ 2$ oxidation state.Hence, statement (B) is correct.
(C) All electrons are paired in the compounds of zinc, cadmium and mercury. Hence, they are diamagnetic in nature. Hence, statement (C) is incorrect.
(D) $Zn, Cd$ and $Hg$ are soft metals as all electrons are paired and metallic bonds are not strong enough. Thus, statement (D) is correct.