I was looking at this Sapling homework and the student is supposed to determine the relative chemical shift of 'A' vs 'B' (shown in an attached picture), which are diastereotopic vinylic methylene hydrogens.
It seems to me the only obvious way to tell them apart would be the relative coupling constant. 'A' should have a larger coupling constant with 'C' because it is trans to 'C'. This was pretty hard to even read in the question, because there was no zoom on the relevant splitting patterns.
According to whoever wrote the question on this Sapling assignment, 'A' should have a higher chemical shift because it is "closer to the oxygen". Does this logic make any sense? A and B the same bond distance away from the oxygen. Is there any obvious relationship in terms of closeness in physical space that correlates with chemical shift?