The correct option is D S2−
Given, the organic compound has C,H,N,S and O
In Lassaigne's test, the elements present in a compound are converted from covalent to ionic form by fusing the organic compound with Sodium (Na) metal because ionic forms are more reactive.
Thus, carbon and nitrogen will form cyanide ion and Na2S will be formed from sulphide ion.
Since, both nitrogen and sulphur are present in the organic compound, sodium thiocyanate is formed.
Na+C+NΔ⟶NaCN2Na+SΔ⟶Na2SNa+C+N+SΔ⟶NaSCN
Cyanides, sulphides and thiocyanate of sodium formed on sodium fusion are extracted from the fused mass by boiling with water.
This extract is known as Sodium Fusion Extract (Lassaigne Extract).
Thus, NO−3 is not present in the Lassaigne's Extract.
Therefore, the correct options are (b), (c) and (d).