Which one of the following is the correct order of reagents to be used to convent [A] to [X] ?

$$ \text { Reagents: } \mathrm{PCC}, \mathrm{PCl}_5, \mathrm{LiAlH}_4, \frac{\mathrm{KCN}}{\mathrm{H}_3 \mathrm{O}^{+}} $$

$$\text { Identify }[\mathrm{B}] \text { and }[\mathrm{C}] \text { formed in the reactions given below. }$$

Which one of the following statements is incorrect regarding acetal and ketal formation when Propanal and Propanone are separately reacted with Ethanol in presence of anhydrous $$\mathrm{HCl}$$ gas.

A Carbonyl compound $$\mathrm{X}$$ when reacted with Methyl magnesium bromide followed by hydrolysis gave product $$\mathrm{Y}$$. When $$\mathrm{Y}$$ is heated with $$\mathrm{Cu}$$ at $$573 \mathrm{~K}$$, it gave $$\mathrm{Z}$$ (2- Methylbut-2-ene) as one of the products. Identify $$\mathrm{X}$$.