Question: who is the biggest owner of us debt
[{'answer': 'China', 'provenance': [{'wikipedia_id': '322221', 'title': 'National debt of the United States', 'start_paragraph_id': 52, 'start_character': 249, 'end_paragraph_id': 52, 'end_character': 254, 'bleu_score': 1.0, 'section': 'Section::::Debt holdings.:Foreign holdings.\n'}]}, {'provenance': [{'wikipedia_id': '322221', 'title': 'National debt of the United States', 'start_paragraph_id': 16, 'start_character': 0, 'end_paragraph_id': 16, 'end_character': 446, 'bleu_score': 0.565368184233309, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15885623924189022364}, 'section': 'Section::::Valuation and measurement.:Public and government accounts.\n'}]}]