Question: the elements c n and o are contained in
[{'answer': 'Period 2', 'provenance': [{'wikipedia_id': '86350', 'title': 'Period (periodic table)', 'start_paragraph_id': 10, 'start_character': 11, 'end_paragraph_id': 10, 'end_character': 19, 'bleu_score': 1.0, 'section': 'Section::::Periods.:Period 1.\n'}]}, {'provenance': [{'wikipedia_id': '86350', 'title': 'Period (periodic table)', 'start_paragraph_id': 11, 'start_character': 0, 'end_paragraph_id': 11, 'end_character': 150, 'bleu_score': 0.910879922930628, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4225727522011442698}, 'section': 'Section::::Periods.:Period 2.\n'}]}]