Question: what region was referred to as the powderkeg of europe
[{'answer': 'the Balkans', 'provenance': [{'wikipedia_id': '1773954', 'title': 'Powder keg of Europe', 'start_paragraph_id': 1, 'start_character': 50, 'end_paragraph_id': 1, 'end_character': 61, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1773954', 'title': 'Powder keg of Europe', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 398, 'bleu_score': 0.9712154609069981, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13629078058936493776}, 'section': 'Section::::Abstract.'}]}]