A narrative poem, often sung, is a:

1. A ballad is a form of verse, often a narrative set to music. 2. A sonnet has fourteen lines, an elegy mourns, and an ode praises. 3. So a story told in sung verse is a ballad. **Why not the others:** A sonnet is a fourteen-line poem, an elegy reflects on grief, and an ode praises a person or event. _Source: Wikipedia, "Ballad", section "introduction" (revision 1377339715)_