Question: who played the role of achilles in troy
[{'answer': 'Brad Pitt', 'provenance': [{'wikipedia_id': '323715', 'title': 'Troy (film)', 'start_paragraph_id': 1, 'start_character': 210, 'end_paragraph_id': 1, 'end_character': 219, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '323715', 'title': 'Troy (film)', 'start_paragraph_id': 12, 'start_character': 0, 'end_paragraph_id': 12, 'end_character': 33, 'bleu_score': 0.5081327481546141, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16547436342608492819}, 'section': 'Section::::Cast.\n'}]}]