The compound that cannot act both as oxidising and reducing agent is:

A compound can act as both oxidizing and reducing agent when it is in intermediate oxidation state and not in highest or lowest oxidation state

Calculating oxidation of given compound we get

Oxidation number of oxygen in $H_2{O}_2$ is -1

Oxidation number of Nitrogen in ${HNO}_2$ is +3

Oxidation number of phosphorus in $H_3{PO}_4$ is +5

Oxidation number of sulphur in $H_2{SO}_3$ is +4

Here only phosphorus oxidation state is maximum possible i.e equal to group number and it can only act as oxidising agent all other have intermediate oxidation state and thus can act as both

Hence option (C) is the correct answer.