Let me make this very very clear. I know very little about interpreting NMR spectra. The first primitive NMR unit that was suggested (it had not been built) was 63 years ago and I was in my last year of graduate school so you mustn't take me seriously. However, as I understand it the H spectra shifts come from the environment the H. So here's what I think. I think the first three are right but I disagree with the last one. That CH3 is one of a kind; i.e., it is attached to a CH2 group. The other two CH3 groups are attach to a CH and not a CH2; therefore, I would think 3 is the correct answer for the last one. But you should definitely get a second third opinion. Good luck.
