The addition of HBr to propene (no peroxide) gives mainly 2-bromopropane because the intermediate formed by proton addition is:

1. Athe primary $\mathrm{CH}{}_3\mathrm{CH}{}_2\mathrm{CH}{}_2{}^{+}$ cation
2. Bthe carbanion $\mathrm{CH}{}_3\mathrm{CH}{}^{-}\mathrm{CH}{}_3$
3. Ca free radical $\mathrm{CH}{}_3\mathrm{CH}{}^{\bullet }\mathrm{CH}{}_3$
4. Dthe more stable secondary $(\mathrm{CH}{}_3){}_2\mathrm{CH}{}^{+}$ cation