Question: what type of joint is the atlanto occipital
[{'answer': 'synovial joint', 'provenance': [{'wikipedia_id': '5032480', 'title': 'Atlanto-occipital joint', 'start_paragraph_id': 1, 'start_character': 157, 'end_paragraph_id': 1, 'end_character': 171, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '5032480', 'title': 'Atlanto-occipital joint', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 171, 'bleu_score': 0.9271474438253491, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12684774459329452640}, 'section': 'Section::::Abstract.'}]}]