Which one of the following choices is a common theme found in lyric poetry?
equality
nature
humor
mystery

Nature is commonly found in lyric poetry, especially in the romanticism period, and transcendentalist american poetry.

Answer;
Nature;
Nature is the theme that is commonly found in Lyric poetry, especially in the romanticism period, and transcendentalist american poetry. 
Lyric is a brief subjective poem strongly marked by imaginations, melody, and emotion, and creating a single unified impression.