Tertiary alkyl halides are practically inert to substitution by the $S_N2$ mechanism due to:

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$ :
Assertion $(A)$ : $S_N2$ reaction of $C_6H_5CH_2Br$ occurs more readily than the $S_N2$ reaction of $CH_3CH_2Br$.
Reason $(R)$ : The partially bonded unhybridized $p$-orbital that develops in the trigonal bipyramidal transition state is stabilized by conjugation with the phenyl ring.
In the light of the above statements,choose the most appropriate answer from the options given below:

Consider the following bromides. What is the correct order of $S_N1$ reactivity?

The order of reactivity of the following alkyl halides for a $S_N2$ reaction is

Rank the following compounds in order of decreasing rate of solvolysis with aqueous ethanol (fastest $\to$ slowest):
$(1)$ $CH_2=C(CH_3)Br$
$(2)$ $1-bromo-1-methylcyclohexane$
$(3)$ $CH_3-CH(Br)-CH_2-CH(CH_3)_2$

Among $CH_3F$,$CH_3Cl$,$CH_3Br$,and $CH_3I$,which one does not give methane on reduction?