Question: who plays marty in back to the future
[{'answer': 'Michael J. Fox', 'provenance': [{'wikipedia_id': '399100', 'title': 'Marty McFly', 'start_paragraph_id': 1, 'start_character': 132, 'end_paragraph_id': 1, 'end_character': 146, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '399100', 'title': 'Marty McFly', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 441, 'bleu_score': 0.744746425310967, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9316539079619274313}, 'section': 'Section::::Abstract.'}]}]