Question: when did riyadh become the capital of saudi arabia
[{'answer': 'September 1932', 'provenance': [{'wikipedia_id': '51554', 'title': 'Riyadh', 'start_paragraph_id': 13, 'start_character': 387, 'end_paragraph_id': 13, 'end_character': 401, 'bleu_score': 1.0, 'section': 'Section::::History.:Third Saudi State.\n'}]}, {'provenance': [{'wikipedia_id': '51554', 'title': 'Riyadh', 'start_paragraph_id': 13, 'start_character': 0, 'end_paragraph_id': 13, 'end_character': 1002, 'bleu_score': 0.9890406822930451, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7559492545150121591}, 'section': 'Section::::History.:Third Saudi State.\n'}]}]