Answer : The balanced oxidation-reduction reaction is,

In this reaction, the 'S' atom shows oxidation and 'N' atom of
shows reduction.
Explanation:
Redox reaction : It is a type of reaction in which an oxidation and reduction reaction takes palace simultaneously.
Oxidation : The loss of electrons and gain of oxygen or increase in the oxidation number is an oxidation.
Reduction : The gain of electrons and loss of oxygen or decrease in the oxidation number is a reduction.
The balanced redox reaction will be,

From this we conclude that, the 'S' atom is oxidized due to increase in the oxidation number from 0 to (+6) and 'N' atom of
is reduced due to decrease in the oxidation number from (+5) to (+2). So, 'S' atom shows oxidation and 'N' atom shows reduction.