Question: what is the last name of the current english royal family
[{'answer': 'Mountbatten - Windsor', 'provenance': [{'wikipedia_id': '46542', 'title': 'British royal family', 'start_paragraph_id': 4, 'start_character': 287, 'end_paragraph_id': 4, 'end_character': 307, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '46542', 'title': 'British royal family', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 732, 'bleu_score': 0.9170114037386771, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16125473688535856471}, 'section': 'Section::::Abstract.'}]}]