What is the purpose of the raised 7th note in the harmonic form of minor scales?

The raised 7th note in the harmonic form of minor scales serves a crucial role in building tension and providing a sense of resolution in musical compositions. By raising the 7th degree of the scale, the harmonic minor scale creates a leading tone, which is a note that strongly resolves to the tonic or root note. This leading tone leads to a stronger pull towards the tonic, thereby enhancing the directionality of the music.

In practical terms, this means that when a melody or harmonic progression approaches the tonic, the raised 7th note heightens the listener's anticipation and desire for that resolution. This characteristic is particularly effective in establishing a strong harmonic foundation, which is why it is commonly used in various musical styles to create a sense of drama and resolution.

The other options do not accurately capture the main purpose of the raised 7th note. While maintaining the scale's original pitch or simplifying the melody may be relevant in different contexts, they do not reflect the unique functional role that the raised 7th plays in harmonic structure. Similarly, while there may be moments of natural resolution in music, the specific tension and leading tone quality created by raising the 7th in minor scales is what distinctly defines its purpose in harmonic progressions.