Which of the following compounds will dissolve in an alkali solution after it has undergone reaction with Hinsberg reagent?

Methyl  amine ( a primary amine) will dissolve in an alkali solution after it has undergone reaction with Hinsberg reagent (benzene sulphonyl chloride).

${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{SO}}_2\mathrm{Cl}+{\mathrm{CH}}_3{\mathrm{NH}}_2\to {\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{SO}}_2{\mathrm{NHCH}}_3\stackrel{\mathrm{KOH}}{⟶}$

${\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{SO}}_2{\mathrm{NKCH}}_3\text{ (watersoluble) }$

Thus the correct answer is ${\mathrm{CH}}_3{\mathrm{NH}}_2$.