Which scale represents the Lydian mode?

The Lydian mode is characterized by its unique interval structure, specifically the presence of a raised fourth scale degree in relation to the major scale. In the context of the choices provided, the correct answer highlights the F scale with a sharp fourth note (#4).

In the key of F major, the natural notes are: F, G, A, Bb, C, D, E. When you apply the Lydian mode to this key, the scale becomes: F, G, A, B, C, D, E. The notable point here is that the fourth scale degree has been raised from Bb to B, which is what distinguishes the Lydian mode from the standard major scale. This raised fourth contributes to the mode's distinctive sound, often perceived as bright and uplifting.

Understanding the structure of the Lydian mode showcases its versatility in both composition and improvisation, as it introduces a tension that resolves nicely within musical contexts. This raised fourth degree opens up new harmonic possibilities that are commonly exploited in various genres of music.