Which non-chord tone is approached by leap and resolved by step in the opposite direction?

The correct answer is the appoggiatura, which is a non-chord tone that is typically approached by a leap and resolved by a step in the opposite direction. This means that when a melody includes an appoggiatura, the note that is considered the appoggiatura is initially reached by jumping from one note to another, often creating a dissonance with the main chord tones. Following this leap, the appoggiatura then resolves to a chord tone by moving in the opposite direction, creating a consonance.

In contrast, other non-chord tones like suspensions and retardations involve a different relationship with the surrounding notes. A suspension is held from a previous note and resolved down by step, making its approach and resolution distinct from an appoggiatura. An escape tone, on the other hand, is approached by step and resolved by leap in the opposite direction, which is also different from the leap-to-step nature of the appoggiatura. Understanding these distinctions is essential in music theory as it helps in recognizing how different non-chord tones function within melodic lines.