The Lassaigne test is used for the detection of which of the following elements?

In the qualitative test for the identification of the presence of phosphorus,the compound is heated with an oxidizing agent. It is further treated with nitric acid and ammonium molybdate,respectively. The yellow-coloured precipitate obtained is:

During the detection of phosphorus in an organic compound,which of the following is formed to produce a yellow color?

Which of the following compounds would give the following set of qualitative analysis?
$(i)$ Fehling's Test : Positive
$(ii)$ $Na$ fusion extract upon treatment with sodium nitroprusside gives a blood red colour.

Given below are two statements:
Statement $I$ : Sulphanilic acid gives esterification test for carboxyl group.
Statement $II$ : Sulphanilic acid gives red colour in Lassaigne's test for extra element detection.
In the light of the above statements,choose the most appropriate answer from the options given below :

The violet color obtained in the Lassaigne's test for a sulfur-containing compound is due to the formation of which species?