Shown below is the structure of one of the methyl ester biodiesel products together with its 130 NMR spectrum. Several of the peaks in the NMR spectrum are indicated by letters, A - D and several of the protons in the structure are indicated by Roman numerals, I - IV. III III HC=CH HC=CH CHE H3CO II CHE 1 CH3 IV B D . A 180 160 140 120 80 100 PPM 60 40 20 Decide which of the carbons indicated I - IV correspond to which of the NMR signals, A-D. D A 180 160 740 120 100 80 60 40 20 PPM Decide which of the carbons indicated I - IV correspond to which of the NMR signals, A-D. a. Choose the correct option for A Select] b. Choose the correct option for B (Select)