Fitting of the CH₃OH bands at 3.94 and 9.74 μm. Top panel: the NIRSpec IFU spectrum of B1-c (solid black) and the local continuum of the 3.94μm CH₃OH band fit by a 3rd-order polynomial (dashed red). Bottom-left panel: best-fit results of the observed absorption complex between 3.75 and 4.03 μm (black, the same as in the top panel but in optical depth scale). The shaded regions in red and yellow correspond to the CH₃OH and H₂S components, respectively. The overall best-fit spectrum is shown in dashed green. Bottom-right panel: the observed 9.74 μm band in the MIRI-MRS spectrum (black) overlaid with the CH₃OH:H₂O lab spectrum (red) scaling with the same factor as in the middle panel.