What type of music is characterized by lengthy compositions with varied repetitions?

The correct choice relates to classical music, which is known for its lengthy compositions that often feature complex structures and themes that are developed and varied throughout the piece. Classical music frequently utilizes the technique of repetition with variation, where a theme may reappear but is altered in terms of harmony, instrumentation, or rhythm, creating a depth of movement and emotion throughout the work. This characteristic is especially evident in the symphonic works of composers like Beethoven, or in the thematic developments found in the compositions of Mozart and Brahms.

In contrast, popular music typically favors shorter compositions with a focus on catchy hooks, while jazz often emphasizes improvisation and spontaneity, leading to more flexible and shorter forms rather than lengthy, structured pieces. Rock music, while it can have extended solos or arrangements, generally maintains a concise format focused on lyrical content and a strong rhythmic drive, rather than the thematic complexity and variation seen in classical music. Therefore, classical music stands out for its elaborate lengths and the sophisticated treatment of musical ideas.