Dereddened flux ratios. The H II region–like galaxies ("H II") are located to the left of the solid curve while LINERs ("L") and Seyfert 2 galaxies ("S") are located on the right. Seyfert 2 galaxies present [O III] ﹩\lambda 5007/ \mathrm{H}\,\beta \geq 3﹩ (solid horizontal lines). Seyfert 1 galaxies are not shown in the diagrams.