What distinguishes a prelude from a fugue?

The distinction between a prelude and a fugue is clearly outlined by their structural and functional characteristics, especially in the context of Western classical music. A prelude serves as an introductory piece that often sets the tone and harmonic framework for a larger work or suite, while a fugue is a specific form of counterpoint that elaborates on a single theme or subject through interwoven melodies.

In a prelude, the emphasis is generally on establishing mood and exploring harmonic possibilities, often leading into subsequent movements or pieces, making it a versatile opening work. On the other hand, a fugue is intricately designed to develop a musical theme through imitative counterpoint; it showcases how voices or instruments can intertwine melodically and rhythmically while maintaining harmonic coherence.

This response to the question highlights the functional role of each term, establishing that the prelude's role is more about introduction and smooth transitions, whereas the fugue's essence lies in the complex interplay of musical lines derived from a single theme. The other options do not capture this nuanced differentiation.