Spectra of all CH₃OH transitions used in current study. Each panel presents spectral data from the $0\stackrel{″}{.}8\times 0\stackrel{″}{.}8$ CND-R1 region from the data cube at their original spectral resolution (Δv ∼ 4 − 6 km s⁻¹) as a solid orange curve. The solid black vertical lines are the frequency references using CH₃OH lines with the lowest E_u in each group. The gray dashed vertical lines are adjacent CH₃OH lines potentially covered by our spectral setup. Velocities refer to v_sys, LSRK = 1120 km s⁻¹. The blue shaded area indicates the velocity coverage we use to derive the velocity-integrated line intensities in our analysis. The gray dashed horizontal line gives the zero-baseline reference.