trace ROOR CH2 CH2 CH3 Br Br Br CH2 CH2CH2 CH2 CH CH2 Br Br

trace ROOR CH2 CH2 CH3 + Br Br Br CH2 CH2-CH2 CH2 CH CH2 Br Br CH2 CH2 CH CH- CH2 CH3

Solution

N- bromo succinamide is an reagent which brominate allylic or benzylic carbons I,e it gives allylic or benzylic halogenation reaction

In the options give a and b halgenation has taken place to the side chain and not the benzylic position

In option c halogenation has taken at phenylic carbon

But only in option d the halogenation has taken place at benzylic position hence the answer is option d.

Note: benzylic carbon/ position is the saturated carbon attached directly to the benzene ring.