The answer is (d): the one at the left is a scale and the one at the right is a major chord, as can be heard by clicking your mouse on either of the photographs to hear its notes.
The clue that gives this one away is that there is a greater variation in the length of the ribbons in the photograph at the right than in the photograph at the left. This means that there is a greater variation in the notes, hence the shuntaphone at the left must be the scale (notes closer together) and the shuntophone at the right the chord (notes further apart).
