You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Classical_music

Context:
Works of classical repertoire often exhibit complexity in their use of orchestration, counterpoint, harmony, musical development, rhythm, phrasing, texture, and form. Whereas most popular styles are usually written in song forms, classical music is noted for its development of highly sophisticated musical forms, like the concerto, symphony, sonata, and opera.

Question:
The concerto, symphony, sonata and opera are examples of what type of musical forms?

sophisticated