Option B. F Ab and C is an example of a minor chord.
A minor chord is a three-note chord consisting of a root note, a minor third, and a perfect fifth above the root. The distance between the root note and the minor third is three half steps (or three semitones), while the distance between the root note and the perfect fifth is seven half steps (or seven semitones).
In option B, the root note is F, the minor third is Ab (which is three half steps above F), and the perfect fifth is C (which is seven half steps above F). Therefore, F Ab and C form an F minor chord.