In a sonata, the theme(s) presented in the new key area in the exposition are repeated in the recapitulation in the B) tonic key. A sonata is a type of musical structure which is used in the middle of the 18th or the Classical era. This music structure has three major part as its foundation which is known as the exposition, the development, and the recapitulation. A tonic key is a format place in the recapitulation where the repeated theme returns.