Which of the following is a source of tonal rhythm?

The recurrence of a single tone serves as a source of tonal rhythm because it establishes a tonal center or anchor around which rhythmic patterns can evolve. This repetition creates familiarity and a sense of stability in the music, allowing listeners to recognize patterns and phrasing related to that tonal center. This foundational tone can be manipulated rhythmically, leading to various rhythmic structures while maintaining a coherent tonal identity.

In tonal music, the recurrence of this single tone can play a crucial role in developing motifs, which can then be elaborated upon or varied throughout a piece. This is especially important in styles where melody and harmony are intertwined with rhythmic elements. The tone provides a grounding effect, contrasting with the surrounding rhythmic activity, thus enhancing the overall musical texture.

The other options relate to rhythm in different contexts but do not specifically address tonal rhythm. For instance, rhythmic inconsistency disrupts the flow rather than providing a stable foundation for tonal exploration. Syncopation adds complexity and off-beat accents but varies the existing rhythmic patterns rather than establishing a tonal center. Melodic disjunction refers to leaps in melody that may create a sense of fragmentation, which does not contribute directly to the notion of a tonal rhythm based solely on repetition of a single tone.