Question: what ring shaped structure forms the lower portion of the larynx
[{'answer': 'Cricoid cartilage', 'provenance': [{'wikipedia_id': '49375', 'title': 'Larynx', 'start_paragraph_id': 3, 'start_character': 350, 'end_paragraph_id': 3, 'end_character': 367, 'bleu_score': 1.0, 'section': 'Section::::Structure.\n'}]}]