Which statement is true about the harmonic minor scale?

The statement that the harmonic minor scale has a unique seventh degree that is raised is accurate and crucial for understanding the scale's structure. In the harmonic minor scale, the seventh degree is elevated by a half step compared to the natural minor scale, creating a distinctive sound often associated with classical and traditional music. This raised seventh degree introduces a leading tone, which provides a strong resolution to the tonic, enhancing harmonic function and emotional expression within a piece.

The presence of this raised seventh degree is particularly significant in Western music, where it contributes to the harmony and movement within chord progressions, particularly in cadences that guide the listener back to the tonic chord.

Other options, while presenting different characteristics of scales, do not apply to the harmonic minor as accurately. For instance, the harmonic minor scale is not defined primarily by whole steps or by raising the sixth scale degree, and it is definitely not synonymous with the natural minor scale, which does not feature the raised seventh. Understanding the unique properties of the harmonic minor scale, notably the raised seventh, allows musicians to employ it effectively in various musical contexts.