Question: which country has long occupied korea by the start of world war 2
[{'answer': 'Japan', 'provenance': [{'wikipedia_id': '341418', 'title': 'Korea under Japanese rule', 'start_paragraph_id': 0, 'start_character': 12, 'end_paragraph_id': 0, 'end_character': 17, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]