The major product formed in the following reaction is :

$\mathrm{CH}_{3} \mathrm{CH}(\mathrm{Br}) \mathrm{CH}_{2} \mathrm{CH}\left(\mathrm{CH}_{3}\right)_{2}$

$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}(\mathrm{Br}) \mathrm{CH}\left(\mathrm{CH}_{3}\right)_{2}$

$\mathrm{Br}\left(\mathrm{CH}_{2}\right)_{3} \mathrm{CH}\left(\mathrm{CH}_{3}\right)_{2}$

$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{C}(\mathrm{Br})\left(\mathrm{CH}_{3}\right)_{2}$