The unknown for Prompt C was manually solved by the author of this manuscript using the 9 pieces of information provided by the professor. In general, each spectra were in agreement, with the most challenging aspects being that the molecule was symmetric, and there was a doublet of doublets for the CH2 protons closest to the ester functional groups. None of the LMMs commented on the last three pieces of information which included a 13C-NMR and 2 DEPT-NMR spectra, possibly due to LMM context window or data fusion limitations. Several models were able to provide rational EI MS interpretations, with GPT-5 having greater interpretability over ChatGPT-4o for 1H-NMR, but both of these models were not able to provide the correct solution, with scores of 3/5, seen in Figure .