Visual test on the primacy of bulge mass for predicting quenching. Disk mass vs. bulge mass, colour coded by total stellar mass (left panel) and the fraction of quenched galaxies (right panel). In both panels iso-mass and iso-morphology (i.e. B/T) lines are drawn to guide the eye, shown in black and magenta (respectively). Quenched central galaxies typically have high bulge masses. Note also that at a fixed stellar mass galaxies may be either star forming or quenched dependent upon B/T; and yet at fixed B/T galaxies may be either star forming or quenched dependent upon M_*. Moreover, there is little-to-no visual dependence of quenching on disk mass explicitly. Hence, quenching proceeds most closely with increasing bulge mass. This provides a simple visual confirmation of the primary result from the RF analysis in the left panel of Fig. 4.