The structure of the product ' $Z$ ' in the reaction sequence is

In the given reaction sequence, conversion of $X$ to $Y$ is an example of

$$ \text { Match the following } $$

The correct answer is

Consider the reaction sequence

$$ \text { Dimethyl ketone } \xrightarrow[\text { (ii) } \mathrm{H}_2 \mathrm{O}]{\text { (i) } \mathrm{CH}_3 \mathrm{MgCl}} X \xrightarrow[\text { (ii) } \mathrm{CH}_3 \mathrm{Br}]{\text { (i) } \mathrm{Na}} Y $$

How many $s p^3$ carbons are present in $Y$ ?