Question: which airport in london is closer to the city
[{'answer': 'City', 'provenance': [{'wikipedia_id': '36098068', 'title': 'Airports of London', 'start_paragraph_id': 3, 'start_character': 11, 'end_paragraph_id': 3, 'end_character': 15, 'bleu_score': 1.0, 'section': 'Section::::International airports.\n'}]}]