Series / Analogy / Classification: Choose the figure which is different from the rest.

In all other figures (A, B, D, and E), the inner polygon has more sides than the outer polygon (e.g., a pentagon inside a hexagon, a square inside a diamond, a pentagon inside a square frame, and a hexagon inside a diamond frame). In Option C, however, the inner square (4 sides) is enclosed by an outer triangle (3 sides), reversing this relationship.