Final answer:
The work 'On the Morning of Christ's Nativity' is accurately described as a religious poem that depicts the birth of Jesus, making use of scenes and themes common to the Nativity narrative.
Step-by-step explanation:
The literary work On the Morning of Christ's Nativity is best described as a religious poem that describes the birth of Christ. This differs from a sonnet which customarily has 14 lines, a specific rhyme scheme, and often includes a volta indicating a shift in thought. On the Morning of Christ's Nativity focuses on the Nativity of Christ, drawing upon biblical narratives and expressing reverence for this central event in Christian theology.
The poem does not align with the other options such as being an epic poem with a heroic protagonist, as its central figure is an infant, nor is it a comedy focused on nativity scenes. Given the poem's focus on the holy birth, its portrayal of divine elements, and its form that is neither a sonnet nor an epic, the description as a religious poem is the most appropriate.