Question: who is the british ambassador to the us
[{'answer': 'Sir Kim Darroch', 'provenance': [{'wikipedia_id': '611426', 'title': 'List of ambassadors of the United Kingdom to the United States', 'start_paragraph_id': 71, 'start_character': 23, 'end_paragraph_id': 71, 'end_character': 38, 'bleu_score': 1.0, 'section': 'Section::::Heads of mission.:Ambassador extraordinary and plenipotentiary (from 1893).\n'}]}]