Deflector galaxy and AGN host galaxy selection. We display the following four galaxy properties: redshift (z), stellar mass (﹩\mathrm{log}({M}_{* }/{M}_{\odot })﹩), effective size (﹩\mathrm{log}({R}_{{\rm{eff}}}/{\rm{kpc}})﹩), and absolute brightness (M_i). Left: in gray, we show properties of a sample of randomly selected galaxies from a cone; in red, we show massive elliptical galaxies that constitute the lenses in our sample. The selection of galaxies is intrinsic, i.e., more massive galaxies act as lenses. Right: in gray, we show the population of galaxies that contain an AGN; in blue, we show the AGN containing galaxies in our sample that are lensed by a massive foreground galaxy. The selection on AGN host galaxies in this case arises from cuts placed to ensure that these systems are detectable in LSST. Thus, this selection of AGN host galaxies in blue is observationally imposed, rather than intrinsic.