Bach, J.S., Minuet in G Major, BWV Anh. 116, from Notebook for Anna Magdalena/Mason
One of the first pieces of Bach (or attributed to Bach) that a student might encounter. The repetitive nature of the difficult sections (they come back) ameliorates the overall difficulty. This is a long piece, and could realistically be considered a more difficult 4 or less difficult 5. I went with 4 because the piece is so jovial and appealing to the student that they don't mind the effort.