Often with benzene, the aromatic protons are grouped in the same environment in the NMR spectrum due to their close proximity to one another. For this question there are 7 aromatic protons, three of which refer to the benzene ring making up the 2,4-DNPH molecule, and the remaining four which make up the benzene ring for one of the side chains.
I'm not quite sure I understand why you think there are 8 proton environments, or why you think the correct answer is 5?!