Product (A) is :
Ph-CH2-Br
It is given that product A is not a result of electrophilic substitution. Also the presence of light (UV - hν) implies free radical substitution.
Cl3C−Brhv−→⋅CCl3+⋅Br
The above homolytic fission is the key to solving this problem.
Once this is accomplished, the Hydrogen atoms not attached to the aromatic ring can only be substituted.