Identify Hinsberg's reagent from the following.

Find the reaction in which the obtained product gives a positive isocyanide test.

For the identification of $\beta$-naphthol using dye test,it is necessary to use :

Given below are two statements:
Statement $I$: All the following compounds react with $p$-toluenesulfonyl chloride:
$C_6H_5NH_2$
$(C_6H_5)_2NH$
$(C_6H_5)_3N$
Statement $II$: Their products in the above reaction are soluble in aqueous $NaOH$.
In the light of the above statements,choose the correct answer from the options given below.

Explain the isocyanide test.

What is Hinsberg reagent?