A reaction produced a mixture of the following two compounds, which were separated. How can we determine which diastereomer is in which separated sample using only the ¹H NMR data?

Structure I is expected to have more complex splitting patterns in its spectrum.

Structure II is expected to have more complex splitting patterns in its spectrum.

Structure I is expected to have more downfield signals in its spectrum.

Structure II is expected to have more downfield signals in its spectrum.