Question: who played doc brown on back to the future
[{'answer': 'Christopher Allen Lloyd', 'provenance': [{'wikipedia_id': '256406', 'title': 'Christopher Lloyd', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 23, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '256406', 'title': 'Christopher Lloyd', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 649, 'bleu_score': 0.8404997466063411, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5570871046596095251}, 'section': 'Section::::Abstract.'}]}]