Which of the following potential energy $(PE)$ diagrams represents the $S_N^1$ reaction?

What is the decreasing order of nucleophilicity for the following nucleophiles?
$A = CH_3COO^-$
$B = CH_3O^-$
$C = CN^-$
$D = CH_3-C_6H_4-SO_3^-$

When chloroform is treated with excess oxygen,it forms:

Increasing order of reactivity of the following compounds for $S_N1$ substitution is:
$(a)$ $(CH_3)_2CH-CH_2Cl$
$(b)$ $CH_3CH_2Cl$
$(c)$ $CH_3O-C_6H_4-CH_2Cl$
$(d)$ $C_6H_5-CH_2Cl$

Consider the given reaction: $CH_3-CH=CH-CH_2-OH \xrightarrow[S_N1]{HBr} [P]$. In the given reaction,the product $[P]$ is:

Identify the statement which is not correct?