Which definition below best describes a definition of theme within poetry?

Question

1. It is the pattern of rhyming lines with a poem.
2. It is the underlying message that a poem conveys.
3. It is the pattern of stressed and unstressed syllables in a poem.
4. It is the type of poem: haiku, limerick, free verse, etc.

Answer 1

2. It is the underlying message that a poem conveys.