Which among the following metals is involved in the preparation of a Grignard reagent?

$3$-Phenylpropene on reaction with $HBr$ gives (as a major product)

The increasing order of the boiling points of the major products $A$,$B$ and $C$ of the following reactions will be:

Arrange the following compounds in decreasing order of their reactivity for hydrolysis reaction:
$(I)$ $C_6H_5-CH_2-Br$
$(II)$ $C_6H_5-CH(Br)-C_2H_5$
$(III)$ $CH_3-CH_2-Br$
$(IV)$ $C_6H_5-CH(Br)-C_6H_5$

In the given reaction sequence,$(X)$ and $(Y)$ are:

From the given pairs of compounds,in which will the first compound undergo $S_N2$ reaction faster?