Which genre best describes Beethoven’s Symphony No. 5?

Beethoven's Symphony No. 5 is best described as a symphony, which is a large-scale orchestral work typically structured in multiple movements. This genre emphasizes the collaborative efforts of various instrumental sections, including strings, woodwinds, brass, and percussion, to create a cohesive musical narrative. Symphony No. 5 is particularly known for its iconic four-note opening motif, which serves as a powerful thematic foundation throughout the piece. The symphonic form allows for both thematic development and orchestral texture, showcasing Beethoven's innovative approach to composition.

As for the other genres mentioned, a sonata typically features a solo instrument or a duo and follows a structure distinct from that of a symphony. A concertino is usually a smaller concerted work involving solo instruments with orchestral accompaniment, often used within the context of a concerto. A string quartet consists exclusively of four string instruments, thus lacking the broader orchestral elements found in a symphony. Each of these forms has its unique characteristics that set them apart from the symphonic tradition exemplified by Beethoven's work.