What is the leading tone in the context of harmonic progression?

In harmonic progression, the leading tone is defined as the raised seventh degree of the scale. This note has a significant function in establishing tension and resolution within music. The leading tone is positioned one half step below the tonic, making it a compelling tone that naturally resolves upward to the tonic note. This upward tendency creates a strong sense of movement and expectation in harmonic structures, especially in classical tonal music.

For instance, in the key of C major, the leading tone is B, which resolves to the tonic note, C. The resolution from the leading tone to the tonic is one of the most fundamental motions in Western harmony and is crucial for creating a sense of closure in a musical phrase.

The other choices do not serve this specific role in harmonic progression. The tonic root is the home base of the scale, the fifth degree contributes stability rather than tension, and the submediant, while it plays a role in harmonic progressions, does not function as a leading tone. Thus, understanding the leading tone's place in tonal harmony is essential for analyzing and composing music that effectively utilizes tension and resolution.