Question: what is the fourth book in the trials of apollo
[{'answer': "The Tyrant 's Tomb", 'provenance': [{'wikipedia_id': '50985871', 'title': 'The Trials of Apollo', 'start_paragraph_id': 16, 'start_character': 1, 'end_paragraph_id': 16, 'end_character': 19, 'bleu_score': 1.0, 'section': 'Section::::Books.:"The Tyrant\'s Tomb".\n'}]}]