The set that represents the pair of neutral oxides of nitrogen is :
\( \mathrm{NO} \) and \( \mathrm{NO_2} \)
\( \mathrm{N_2O} \) and \( \mathrm{N_2O_3} \)
\( \mathrm{NO} \) and \( \mathrm{N_2O} \)
\( \mathrm{N_2O} \) and \( \mathrm{NO_2} \)