To determine the mood of the poster, I would need more context about its visuals, color scheme, imagery, and any text present. However, based on the options provided, if the poster features dark colors, somber imagery, or themes of sadness, "melancholy" or "somber" could be appropriate. If it conveys a sense of calm or peacefulness, "tranquil" would fit. If it's vibrant and lively, "animated" would be the choice.
Please provide more details or description about the poster for a more accurate analysis.