Sodium fusion extract of which compound gives Prussian blue colour with $FeSO_4$?

During Lassaigne's test,if $N$ and $S$ are present individually in an organic compound,they are converted into:

Which one of the following reactions does $NOT$ belong to "Lassaigne's test"?

In the detection test of nitrogen,the Prussian blue colour is due to which compound?

Given below are two statements :
Statement $I :$ In Lassaigne's test,the covalent organic molecules are transformed into ionic compounds.
Statement $II :$ The sodium fusion extract of an organic compound having $N$ and $S$ gives prussian blue colour with $FeSO_4$ and $FeCl_3$.
In the light of the above statements,choose the correct answer from the options given below.

$A$ solution of $m-$chloroaniline,$m-$chlorophenol and $m-$chlorobenzoic acid in ethyl acetate was extracted initially with a saturated solution of $NaHCO_3$ to give fraction $A$. The left over organic phase was extracted with dilute $NaOH$ solution to give fraction $B$. The final organic layer was labelled as fraction $C$. Fractions $A$,$B$ and $C$ contain respectively