Solution:
One of the responding components consistently has a component that can exist in somewhere around 3 oxidation numbers.
(I) The non – metals which can show disproportionation responses are $\mathrm{P}, \mathrm{Cl}$ and $\mathrm{S}$.
(ii) The three metals which can show disproportionation responses are $\mathrm{Mn}, \mathrm{Ga}$ and $\mathrm{Cu}$.