Question: which of the world of warcraft expansions is the oldest
[{'answer': 'The Burning Crusade', 'provenance': [{'wikipedia_id': '379591', 'title': 'World of Warcraft', 'start_paragraph_id': 55, 'start_character': 111, 'end_paragraph_id': 55, 'end_character': 130, 'bleu_score': 1.0, 'section': 'Section::::Development.:Expansions.\n'}]}]