Answer:
B. as a solo instrument.
Step-by-step explanation:
One of the main features of the Classical period was the replacement of the harpsichord by the piano. This was important because the piano, having a more homophonic sound, made it possible to use the instrument together with others in an orchestra and make the dynamics techniques more practicable.
Thus piano compositions have become more complex and detailed than previously seen in harpsichord compositions.