Question: when did smells like teen spirit first air on mtv
[{'answer': '1991', 'provenance': [{'wikipedia_id': '59993', 'title': 'Smells Like Teen Spirit', 'start_paragraph_id': 1, 'start_character': 150, 'end_paragraph_id': 1, 'end_character': 154, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]