What is it when small, medium, and large shapes repeat in a fixed sequence?

Correct answer: Alternating sequence rhythm

The governing concept is rhythmic repetition. The repeating unit contains three sizes—small, medium, and large—and returns in the same order each time. This ordered alternation creates an alternating sequence rhythm, making option C the best answer. It is not random because the order is predictable, and it is not flowing because the question describes a fixed sequence rather than continuous directional movement. The phrase “regular rhythm only” is too vague to identify the specific pattern.