When a design contains one large square with several smaller squares inside it, which proportional relationship is most important?

Correct answer: Relationship of small parts to the large whole

The governing concept is proportion, which compares the size of parts with the size of the whole. Here, each small square must be judged against the enclosing large square and, when relevant, against the other small squares. This comparison determines whether the design looks coherent or awkward, so option B is correct. Colour temperature, line movement, texture and lighting may affect style, but they do not define the stated size relationship.