Which among the following is most common in alkyl halides?

Compare the rate of $E_2$ reaction for the following compounds:
$a$: $(CH_3)_3C-Br$
$b$: $CH_3-CH(Br)-CH_3$
$c$: $CH_3-CH_2-Br$

$CH_3 - CH_2 - CH_2Br + KOH$ (alc.) $\to$ Product
The product in the above reaction is:

Which of the following products is not formed in the following reaction?
$Vinylcyclopentane + HBr \rightarrow ?$

$CH_3Br + Nu^{-} \rightarrow CH_3-Nu + Br^{-}$
The decreasing order of the rate of the above reaction with nucleophiles $(Nu^{-})$ $A$ to $D$ is
$[Nu^{-} = (A) \, PhO^{-}, (B) \, AcO^{-}, (C) \, HO^{-}, (D) \, CH_3O^{-}]$

Select the incorrect option: