a
\(\begin{array}{*{20}{c}} {{\rm{C}}{{\rm{H}}_3} - {\rm{C}}{{\rm{H}}_2} - {\rm{C}}{{\rm{H}}_2} - {\rm{CH}} - {\rm{C}}{{\rm{H}}_3}}\\ {\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|}\\ {\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,Br} \end{array} \xrightarrow[\mathrm{E}_{2}]{Base} \mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}=\mathrm{CH}-\mathrm{CH}_{3}\,+\)

\(\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\)Major,More stable, Saytzeff's product

\(\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}_{2}-\mathrm{CH}=\mathrm{CH}_{2}\)

\(\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\)Minor,less stable, Hofomann's product