Question: who was the british general who surrendered at yorktown
[{'answer': 'Charles Cornwallis', 'provenance': [{'wikipedia_id': '157770', 'title': 'Siege of Yorktown', 'start_paragraph_id': 1, 'start_character': 417, 'end_paragraph_id': 1, 'end_character': 435, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '157770', 'title': 'Siege of Yorktown', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 897, 'bleu_score': 0.9865312178338931, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17475052091502367620}, 'section': 'Section::::Abstract.'}]}]