Question: when did avatar the last airbender first air
[{'answer': 'February 21 , 2005', 'provenance': [{'wikipedia_id': '1620586', 'title': 'Avatar: The Last Airbender', 'start_paragraph_id': 18, 'start_character': 93, 'end_paragraph_id': 18, 'end_character': 111, 'bleu_score': 1.0, 'section': 'Section::::Development.:Conception and production.\n'}]}, {'answer': 'February 2005', 'provenance': [{'wikipedia_id': '1620586', 'title': 'Avatar: The Last Airbender', 'start_paragraph_id': 1, 'start_character': 186, 'end_paragraph_id': 1, 'end_character': 199, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1620586', 'title': 'Avatar: The Last Airbender', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 722, 'bleu_score': 0.8279815003924661, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4048722645719016708}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1620586', 'title': 'Avatar: The Last Airbender', 'section': 'Section::::Development.:Conception and production.\n', 'start_paragraph_id': 18, 'end_paragraph_id': 18, 'meta': {'evidence_span': ['The series was introduced to the public in a teaser reel at Comic-Con 2004, and premiered on February 21, 2005.', 'The series was introduced to the public in a teaser reel at Comic-Con 2004, and premiered on February 21, 2005.\rhighlight sentence(s) containing evidence, not only the answer']}}]}]