i) ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{Cl}\stackrel{\mathrm{KOH}\left(\mathrm{aqueous}\right)}{\to }\mathrm{X}$ 

ii) $\mathrm{X}\underset{170°\mathrm{C}}{\overset{\mathrm{Conc}. {\mathrm{H}}_2{\mathrm{SO}}_4}{\to }}\mathrm{Y}\stackrel{{\mathrm{Cl}}_2/{\mathrm{H}}_2\mathrm{O}}{⟶}\mathrm{Z}$

What is 'Z' ?

i.) ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{Cl}\stackrel{\mathrm{KOH}\left(\mathrm{aqueous}\right)}{\to }{\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}+\mathrm{KCl}$

ii.) ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}\underset{170°\mathrm{C}}{\overset{\mathrm{Conc}. {\mathrm{H}}_2{\mathrm{SO}}_4}{\to }}{\mathrm{CH}}_2=\mathrm{C}{\mathrm{H}}_2\stackrel{{\mathrm{Cl}}_2/{\mathrm{H}}_2\mathrm{O}}{\to }\mathrm{Cl}-{\mathrm{CH}}_2-{\mathrm{CH}}_2-\mathrm{OH}$

In the above reactions, the final product (Z) which is obtained is known as 2-Chloroethanol or Ethylene chlorohydrin.

Hence, the correct answer is option (A) Ethylene chlorohydrin