Question: what key has three flats?
Answer: E-flat major (or the key of E-flat) is a major scale based on E♭, with the pitches E♭, F, G, A♭, B♭, C, and D. Its key signature has three flats: B, E, and A. Its relative minor is C minor, while its parallel minor is E♭ minor (or enharmonically D♯ minor).