Which basic radical(s) decolourize acidic `KMnO_(4)` ?

Explanation

Ferrous and stannous `(Fe^(2+)` and `Sn^(2+)`) both act as reducing agents and decolourize acidic `KMnO_(4)`.
`MnO_(4)^(-) +5Fe^(2+) +8H^(+) to 5Fe^(3+) +Mn^(2+) +4H_(2)O`