Which of the following is NOT a characteristic of the arch form in music?

The correct choice highlights that "Free tempo" is not a characteristic of the arch form in music, which is a structural concept often characterized by its symmetrical and balanced design.

In arch form, one generally sees a clear pattern that includes a buildup and a return to the initial themes, often creating a sense of symmetry. The structure typically includes elements of repetition, especially in reverse order, providing an echo effect that reinforces the central idea presented at the beginning. Sectional structure is also a key component, as it allows for distinct sections of music that fit into the overall arch design.

While tempo can change within a piece, the arch form itself does not dictate a free or unstructured tempo. Instead, the form emphasizes a deliberate and often measured approach to rhythm and phrasing that complements its symmetrical nature. Therefore, the notion of "Free tempo" does not align with the formal characteristics that define arch form in music.