Which sentence has a subject-verb agreement error?

Which of the following statements is not true? comic operas in the classical period treated middle-class subjects, had folklike tunes, and sometimes even ridiculed the aristocracy. townspeople organized public concerts where, for the price of admission, they could hear the latest symphonies and concertos. joseph haydn's contract of employment shows that he was considered a skilled servant, like a gardener or gamekeeper. political and economic power shifted during the classical period from the middle class to the aristocracy and the church.