Nitrobenzene on nitration gives

Assertion : The presence of nitro group facilitates nucleophilic substitution reactions in aryl halides.
Reason : The intermediate carbanion is stabilized due to the presence of nitro group.

The decreasing order of reactivity of the following compounds towards $Na^{\oplus} O^{\ominus} Me$ is:

$Ph-NO_2 + Et-Cl \xrightarrow{AlCl_3} (A)$,Product $(A)$ of the given reaction is

In the following reaction sequence,the major product $B$ is:

Chlorobenzene $(X)$ when reacted with reagent '$A$' gets converted to phenol $(Y)$. The major product obtained from nitration of $X$ gets converted to $p$-nitrophenol $(Z)$ by reaction with reagent $B$. What are $A$ and $B$ respectively?