A, F) The peak at 8.78 ppm corresponds to these hydrogen atoms, which have a higher ppm because of the deshielding effect since it is very proximal to a Nitrogen atom.
B, C) The peak at 2.52 ppm to 2.80 ppm corresponds to these hydrogen atoms. Both represent multiplets that are created by the effect of the three bond neighbors.
D) The peak of 8.14 ppm represents this aromatic hydrogen atom that appears at a doublet of doublets due to its neighbor.
E) This peak at 7.43 ppm is another aromatic hydrogen that also has a splitting pattern of doublets of doublets due to its three-bond neighbor.
G) The peak at 9.77 ppm is a hydrogen atom off of a nitrogen atom, which creates a large deshielding affect that raises its ppm.
H, J) The peaks at 3.14 ppm to 3.30 ppm are create a triplet of triplets peaks because these hydrogen atoms sp3 hydrogen atoms that have a slight inductive effect due to the double-bonded oxygen atom nearby.
I) The peak at 7.50 ppm represents a multiplet that the hydrogen atoms create due being at a site where the hydrogen atoms are affected by the “I” hydrogen atoms, as well as the “H, J” hydrogen atoms.
K) The peak at 3.70 ppm is a very large, single peak, which is representative of the sp3 hydrogen atoms and the inductive effect of a single-bonded oxygen atom effect.