Question: who fought in the western front in ww1
[{'answer': 'France', 'provenance': [{'wikipedia_id': '51499', 'title': 'Western Front (World War I)', 'start_paragraph_id': 1, 'start_character': 262, 'end_paragraph_id': 1, 'end_character': 268, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'British Empire', 'provenance': [{'wikipedia_id': '51499', 'title': 'Western Front (World War I)', 'start_paragraph_id': 12, 'start_character': 231, 'end_paragraph_id': 12, 'end_character': 245, 'bleu_score': 1.0, 'section': 'Section::::1914.:First Battle of the Marne.\n'}]}, {'answer': 'Belgium', 'provenance': [{'wikipedia_id': '51499', 'title': 'Western Front (World War I)', 'start_paragraph_id': 1, 'start_character': 188, 'end_paragraph_id': 1, 'end_character': 195, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'German Empire'}, {'answer': 'Austria - Hungary'}]