Question: who is the head coach of the baltimore ravens
[{'answer': 'John W. Harbaugh', 'provenance': [{'wikipedia_id': '4438793', 'title': 'John Harbaugh', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 16, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '4438793', 'title': 'John Harbaugh', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 707, 'bleu_score': 0.895594503481538, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15541976545205236892}, 'section': 'Section::::Abstract.'}]}]