Appearance of blood red colour, on treatment of the sodium fusion extract of an organic compound with \( \mathrm{FeSO_4} \) in presence of concentrated \( \mathrm{H_2SO_4} \) indicates the presence of element/s
\( \mathrm{N} \) and \( \mathrm{S} \)
\( \mathrm{Br} \)
\( \mathrm{N} \)
\( \mathrm{S} \)