The correct option is B HNO2
HNO3 oxidation number of N is = +5
Highest O.N., only reduces, acid only oxidising agent.
HNO2 oxidation number = +3
It reduces as well as oxidise, act both oxidising and reducing agent.
H2SO4 oxidation number = +6
Highest O.N., only reduces, act only oxidising agent.
So HNO2 acts both an oxidising as well as reducing agent