@HarjotDhillon @HarjotDhillon -R effect is very much valid as system is conjugated, and -I effect is always valid. Here, -R or electron withdrawing group will destabilise a carbocation (which is already electron deficient), hence in (A), where distance between -R and (+) is maximum, stability is maximum

"Carbon free radicals are better stabilised by -R groups"- carbon free radicals are electron deficient species, so shouldn't they be stabilised by +R,+H,+I, and least of all -R? @Mithoron @YusufHasan

@BongoMan when I said "so no -R effect" I meant -R at para position.

Due to -Y group attached at meta position there is no possibility of -R effect at para position.