Identify the major product $(P)$ for the following reaction sequence:
$1,2-\text{dibromo}-3-\text{ethyl}-4-\text{methylcyclopentane} \xrightarrow[(ii) HBr]{(i) Zn, \Delta} (P)$

Consider the following reaction sequence:
$Cyclohexylidene-methane$ $\xrightarrow[CH_3OH]{Br_2} A$ $\xrightarrow{KCN} B$
Identify the correct structures for $A$ and $B$ from the given options:
$A$ is:
$A) \text{ 1-(bromomethyl)-1-methoxycyclohexane}$
$B) \text{ 1-(methoxymethyl)-1-bromocyclohexane}$
$B$ is:
$C) \text{ 1-(bromomethyl)-1-methoxycyclohexane}$
$D) \text{ 1-(cyanomethyl)-1-methoxycyclohexane}$

Which of the following compounds will not undergo Friedel-Crafts reaction with benzene?

$1$-chlorobutane on reaction with alcoholic potash gives

Most reactive for $S_{N}1$ reaction is

Which of the following alkyl halides is used as a methylating agent?