Final answer:
In music, the term for a recurring musical theme or leitmotif in a composition is a 'motif'. It is a significant element that serves to unify a work and often symbolizes deeper concepts related to the theme.
Step-by-step explanation:
In music, a recurring musical theme or leitmotif in a composition is referred to as a motif. The correct answer to the student's question is option c) Motif. A motif is not limited to music; it can also appear as a significant element in literature, where it recurs throughout a text to draw attention to a theme. Whether it's a certain melody in a symphony or a repeated phrase in literature, a motif serves to unify a composition and can symbolize various concepts, helping to convey deeper meanings and themes.