When $but-3-en-2-ol$ reacts with aqueous $HBr$,which of the following products is obtained?

What are $X$ and $Y$ respectively in the following reaction sequence?
$C_3H_6$ $\xrightarrow[\text{(C}_6\text{H}_5\text{CO)}_2\text{O}_2]{\text{HBr}} X$ $\xrightarrow{\text{Na/ dry ether}} Y$

The product $(B)$ of the above reaction is:

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$a$. Benzenediazonium chloride $\xrightarrow{Cu_2Cl_2/HCl}$ Chlorobenzene $+ N_2$	$i$. Wurtz reaction
$b$. Benzenediazonium chloride $\xrightarrow{Cu/HCl}$ Chlorobenzene $+ N_2$	$ii$. Sandmeyer reaction
$c$. $2 CH_3CH_2Cl + 2 Na \xrightarrow{Ether} C_2H_5-C_2H_5 + 2 NaCl$	$iii$. Fittig reaction
$d$. $2 C_6H_5Cl + 2 Na \xrightarrow{Ether} C_6H_5-C_6H_5 + 2 NaCl$	$iv$. Gatterman reaction

Choose the correct answer from the options given below:

The number of all types of isomers of chlorobutane $(C_4H_9Cl)$ is:

The products obtained in the above reactions $(1)$,$(2)$,and $(3)$ are: