In waterlogged soils, such as those used for rice growing, the oxygen level is low. In these conditions, anaerobic bacteria remove nitrogen from the soil, as represented by the sequence below. $\text{NO}_3^-(aq) \xrightarrow{A} \text{NO}_2^-(aq) \xrightarrow{B} \text{NO}(g) \xrightarrow{C} \text{N}_2\text{O}(g) \xrightarrow{D} \text{N}_2(g)$ At which step does the change in oxidation number (oxidation state) of nitrogen differ from the changes in the other steps?
- AA
- BB
- CC
- DD