Quasar selection functions using ground-based data and using BMC, assuming a single contaminating population. Filled contours indicate the case where only galaxies are considered as contaminants, i.e., W_s = 0. Dashed lines indicate the case where only MLTs are considered, i.e., W_g = 0, W_s ≠ 0. Contour intervals are the same in both cases. The contour indicating J = 22 is also shown as a solid green line.