Question: who pioneered the birth control clinic in the united states
[{'answer': 'Margaret Sanger', 'provenance': [{'wikipedia_id': '33286807', 'title': 'Birth control movement in the United States', 'start_paragraph_id': 1, 'start_character': 319, 'end_paragraph_id': 1, 'end_character': 334, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '33286807', 'title': 'Birth control movement in the United States', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 1528, 'bleu_score': 0.949557738243975, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1085564690728866590}, 'section': 'Section::::Abstract.'}]}]