Top: normalized distributions of the nuclear reddening Q_r indices for different classes of nuclear activity (computed following Cid Fernandes et al. 2011) color coded as follows: AGNs are represented by a red line; the PSBs distribution is traced by the blu line; the green line stands for HII-like nuclei and the orange for PASSIVE and Retired galaxies. Bottom: normalized distributions of HII-like nuclei above (red) and below (blue) 10⁹ M_⊙.