When propene reacts with HBr in the presence of organic peroxides, the major product is:

Peroxides switch the mechanism from ionic to free-radical (peroxide / Kharasch effect). The radical adds anti-Markovnikov so Br lands on the *less* substituted carbon — giving 1-bromopropane. The trap is option B (Markovnikov product) — that's the answer without peroxides. The peroxide effect is specific to HBr HCl and HI do not show it.