Identify (X), (Y) and (Z) reagents in the given sequence of reaction.

$\mathrm{CH}\equiv \mathrm{CH}\stackrel{\mathrm{x}}{⟶}{\mathrm{CH}}_3\mathrm{CHO}\stackrel{\mathrm{y}}{⟶}{\mathrm{CH}}_3\mathrm{CH}\left(\mathrm{OH}\right){\mathrm{CH}}_3\stackrel{\mathrm{z}}{⟶}{\mathrm{CH}}_3{\mathrm{COCH}}_3$

 

$$\begin{gathered} \mathrm{HC}\equiv \mathrm{CH}\underset{{\mathrm{H}}_2\mathrm{O}}{\overset{{\mathrm{HgSO}}_4,\mathrm{dil}.{\mathrm{H}}^{+}}{\to }} {\mathrm{CH}}_3\mathrm{CHO} \stackrel{{\mathrm{CH}}_3\mathrm{MgBr}/{\mathrm{H}}_2\mathrm{O}}{\to } {\mathrm{CH}}_3\mathrm{CH}\left(\mathrm{OH}\right){\mathrm{CH}}_3 \\ {\mathrm{CH}}_3\mathrm{CH}\left(\mathrm{OH}\right){\mathrm{CH}}_3 \stackrel{{\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7/{\mathrm{H}}^{+}}{\to } {\mathrm{CH}}_3{\mathrm{COCH}}_3 \end{gathered}$$

Hence, the correct option is (D)

$\begin{array}{r}\mathrm{X}={\mathrm{H}}_2{\mathrm{SO}}_4/{\mathrm{Hg}}^{2+};\mathrm{Y}={\mathrm{CH}}_3\mathrm{MgBr}/{\mathrm{H}}_2\mathrm{O};\\ \mathrm{Z}={\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7/{\mathrm{H}}^{+}\end{array}$