Question: what does nfc and afc stand for in the nfl
[{'answer': 'National Football Conference', 'provenance': [{'wikipedia_id': '615', 'title': 'American Football Conference', 'start_paragraph_id': 1, 'start_character': 222, 'end_paragraph_id': 1, 'end_character': 250, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'American Football Conference', 'provenance': [{'wikipedia_id': '615', 'title': 'American Football Conference', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 28, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '615', 'title': 'American Football Conference', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 728, 'bleu_score': 0.866958844533198, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2337283081302255063}, 'section': 'Section::::Abstract.'}]}]