Which scale raises the 7th degree to create a leading tone, commonly used in harmony?

• A. Natural minor scale
• B. Melodic minor scale
• C. Major scale
• D. Harmonic minor scale

Answer: (D)

The idea here is to create a strong pull to the tonic in harmony. That pull, the leading tone, comes from raising the seventh degree so it sits a half step below the tonic. In a minor key, the natural minor has a flat seventh, which doesn’t provide that leading-tone function. When you raise the seventh, you get the harmonic minor scale, and the note becomes the leading tone. This gives a powerful dominant function to the V chord, resolving decisively to the tonic.

Melodic minor does raise the sixth and seventh when ascending to smooth melodies, but its primary use is melodic line rather than the harmonic function. So for traditional harmony and the strong V to i resolution, the harmonic minor scale is the standard.