The structures along with their codes are given below.
For Compound A:
# of ¹H signals: 3 (as both side chains from carbonyl positions are same) # of ¹³C signals: 4
For Compound B:
# of ¹H signals: 3 (the two methyl groups of isopropyl are equivalent) # of ¹³C signals: 4
For Compound C: # of ¹H signals: 2 (as both side chains from carbonyl positions are same) # of ¹³C signals: 3 For Compound D: # of ¹H signals: 3 # of ¹³C signals: 4
