Grignard reagent can be prepared by 

For the reaction 

Identify $\text{'}\mathrm{Z}\text{'}$ in the following reaction series,

${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_2\mathrm{Br}\stackrel{\mathrm{aq}.\mathrm{NaOH}}{\to },\left(\mathrm{X}\right)\underset{\mathrm{Heat}}{\overset{{\mathrm{Al}}_2{\mathrm{O}}_3}{\to }}\left(\mathrm{Y}\right)\stackrel{{\mathrm{Cl}}_2/{\mathrm{H}}_2\mathrm{O}}{⟶}\left(\mathrm{Z}\right)$
 

For the reaction, 

${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}+\mathrm{HX}\stackrel{{\mathrm{ZnX}}_2}{⟶}{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{X},$ the order of reactivity is:

Consider the following chlorides:

The order of reactivity of $\mathrm{A}, \mathrm{B}, \mathrm{C}$ and $\mathrm{D}$ towards hydrolysis by ${\mathrm{S}}_{\mathrm{N}}1$ mechanism is :