Which of the following is NOT a characteristic of classical music?

The characteristic that is not typically associated with classical music is improvisation. Classical music is predominantly based on written notation, meaning that the composers create detailed scores that performers follow precisely. This focus on written music allows for the intricate and complex harmonic structures that classical music is known for. Additionally, classical compositions are often extended works that can involve elaborate orchestration, often performed by large ensembles such as orchestras.

In classical music, the role of the performer is largely to interpret the written score rather than create music spontaneously as seen in genres like jazz or certain traditional folk music, where improvisation is a fundamental aspect. While there may be moments of improvisation within classical music (e.g., in some historical contexts or during specific performances), it is not a defining characteristic of the genre as a whole. Thus, improvisation stands out as the least representative feature of classical music among the options provided.