[Dan]

Do you think I would be able to argue with my prof that 1) HN(CH3)2, LiAlH4 is correct if he marks it incorrect?

No, it's two steps: 1) HNMe₂; 2) LiAlH₄

Another good alternative is: 1) DIBAL; 2) HNMe₂, NaBH₃CN.

In the latter approach, DIBAL achieves in one step what LiAlH₄/PCC achieves in two. That will probably be easier to argue with the prof, but I'd expect either of those routes to work, and they are certainly both better than the 3 step procedure.