Three students examined the signals in the HNMR spectrum shown below. The first student concludes that these are four singlets representing four magnetically different protons in the molecule. The second student believes that the molecule has two different sets of protons, but that the two resulting signals were split into two doublets. Peaks are indicative of a quartet. The third student believes that a single set of protons is involved, and that the four lines constitute a quartet. Who do you think is correct and why?

Three students examined the signals in the HNMR spectrum shown below. The first student concludes that these are four singlets representing four magnetically different protons in the molecule. The second student believes that the molecule has two different sets of protons, but that the two resulting signals were split into two doublets. Peaks are indicative of a quartet. The third student believes that a single set of protons is involved, and that the four lines constitute a quartet. Who do you think is correct and why?