Question: who pioneered the birth control clinic in the us
[{'answer': 'Margaret Higgins Sanger', 'provenance': [{'wikipedia_id': '20707', 'title': 'Margaret Sanger', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 23, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '20707', 'title': 'Margaret Sanger', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 398, 'bleu_score': 0.905341140211783, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3965659795915812334}, 'section': 'Section::::Abstract.'}]}]