Answer:
C. chromatic scale
Explanation:
Chromatic scale is that formed by 12 notes with semitone intervals between them.
Although the chromatic scale is not usually used to its full extent in musical contexts, small chromatic passages are common, and used from baroque composers like Bach, through romantics, like Chopin, to moderns and contemporaries, like Schoenberg who developed the dodecaphonism.
In the context of popular music, chromatism, that is, the use of passages in semitones, is especially used in improvisation, in the use of approaching or passing notes.
