Which best describes a perfect authentic cadence?

• A. V to I in root position with both chords in root position, ending on the tonic
• B. I to IV progression
• C. V to iv progression
• D. IV to V progression

Answer: (A)

A perfect authentic cadence is a firm, final-sounding resolution that moves from V to I with both chords in root position, ending on the tonic. This option matches that structure exactly: a dominant chord resolving to the tonic, both chords in their root positions, and finishing on the tonic. The strength comes from resolving the dominant to the tonic in full root position, which gives the clearest sense of closure.

The other progressions don’t provide that same finality: I to IV moves away from the tonic, so it doesn’t cadence to a tonic; V to iv uses a minor subdominant instead of resolving to the major tonic in root position; IV to V ends on V, not on the tonic, so it doesn’t close the phrase.