Comparison of the best subset conditions (from left to right): (i) the complete sample, (ii) the brighter BCGs, and combinations of massive clusters and brighter BCGs (iii); massive clusters and redder BCGs (iv), brighter and redder BCGs (v), brighter and redder BCGs and red galaxies (vi), and massive clusters and brighter and redder BCGs and red galaxies (vii). The grey shaded region shows the 1σ region expected from a uniform distribution.