Statement (A): In , ${\mathrm{H}}_2{\mathrm{S}}_2{\mathrm{O}}_8,$one peroxy linkage is present 

Statement (B): In organic compounds, carbon can have any oxidation number from −4 to +4 . 

Statement (C): Nitrogen exhibits more than three oxidation states.

The element carbon, C has four valence electrons it exhibits tetra valency of its compounds. Based on the nature of compound, the oxidation number of carbon varied from −4 to +4 . Nitrogen exhibits different oxidation states in its compounds Ex: In NO, oxidation state of N is +2. In ${\mathrm{NO}}_2,$, oxidation state of N is +4 . In ${\mathrm{N}}_2\mathrm{O},$ the oxidation state of N is +1 . Similarly, in ${\mathrm{N}}_3\mathrm{H},$ the oxidation state of N is $-\frac{1}{3}.$ In ${\mathrm{N}}_2{\mathrm{O}}_5.$the oxidation state of N is +5 .

So, nitrogen exhibits more than three oxidation states in its compounds.

The structure of ${\mathrm{H}}_2{\mathrm{S}}_2{\mathrm{O}}_8$ is as follows: