Top: reduced χ² distributions of the fits to the spectroscopy (left), photometry (middle), and the combined data sets (right panel) as a function of the extinction law. Vertical lines mark the medians of the distributions. Bottom: χ² difference of the best-fitting solutions obtained using δ = −0.4 and δ = −0.7 with respect to δ = 0. Grey dashed lines mark the levels of ±Δχ² = 2.3.