Which mode is described as major but with flattened third and seventh degrees?

• A. Phrygian
• B. Lydian
• C. Mixolydian
• D. Dorian

Answer: (D)

This is about modal scales and how lowering scale degrees changes the mood. The mode described as major with flattening of the third and seventh is Dorian. If you take the major scale for a root note and lower both the third and the seventh degrees, you get the Dorian collection. For example, starting on D and using the notes of the D major family but flattening the third and seventh gives D E F G A B C D. The third from D becomes F (not F#), and the seventh becomes C (not C#). That lowers the tonic’s third to a minor third and the seventh to a minor seventh, producing a minor triad on the tonic (D–F–A) with a D–C interval above the octave. This creates the distinct sound of Dorian: minor in flavor but with a brighter sixth degree that differentiates it from a pure natural minor. Other modes modify different degrees (for example, one alters the second, another the fourth, another the seventh), which is why the description fits Dorian specifically.