) Which of these halogenoalkanes reacts the fastest? \mathrm{CH}_{3} \mathrm{CHBrCH}\left(\mathrm{CH}_{3}\right) \mathrm{CH}_{3} \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CBr}\left(\mathrm{CH}_{3}\right) \mathrm{CH}_{3} \mathrm{CH}_{3} \mathrm{CH}\left(\mathrm{CH}_{2} \mathrm{Br}\right) \mathrm{CH}_{2} \mathrm{CH}_{3} \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}