The correct option is D C1−N and C3−N bonds are of the same length but shorter than the C5−N bond
Due to the steric hinderance of three groups, the −NO2 group go out of the plane with benzene ring and so conjugation of −NO2 group with benzene is slightly diminished. So, C1−N and C5−N bonds are of same length but longer than C3−N bond