Fusion of MnO₂ with KOH in presence of O₂ produces a salt (W). Alkaline solution of W upon electrolytic oxidation yields another salt (X). The manganese containing ions in W and X are Y and Z, respectively. Correct statement(s)is (are)

In aqueous acidic solution, Y undergoes disproportion reaction to give Z and MnO₂

Both Y and Z are colored and have tetrahedral shape

Y is diamagnetic in nature while Z is paramagnetic

In both Y and Z, $\mathrm{\pi }$ - bonding occurs between p- orbitals of oxygen and d- orbitals of manganese