Which of the following pairs of the compounds will produce blood red color in the Lassaigne's test for nitrogen?

When nitrogen and sulphur both are present in the organic compound, they combine during fusion to form sodium thiocyanate (sulphocyanide), This when heated with FeSO₄ ​or FeCl₃​, produces a red blood colouration due to ferric thiocyanate (or sulphocyanide).

Thus, thiourea, and p-sulphanilic acid give red colour on Lassaigne test.