Question: of which country is sofia the capital city
[{'answer': 'Bulgaria', 'provenance': [{'wikipedia_id': '57644', 'title': 'Sofia', 'start_paragraph_id': 1, 'start_character': 49, 'end_paragraph_id': 1, 'end_character': 57, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '57644', 'title': 'Sofia', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 270, 'bleu_score': 0.553082183571684, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7011204966113487250}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '57644', 'title': 'Sofia', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['Sofia ( ; , ) is the capital and largest city of Bulgaria. The city is at the foot of Vitosha Mountain in the western part of the country.', 'Sofia ( ; , ) is the capital and largest city of Bulgaria.', 'Sofia ( ; , ) is the capital and largest city of Bulgaria.']}}]}, {'provenance': [{'wikipedia_id': '44923693', 'title': 'Stolichna Municipality', 'section': 'Section::::Abstract.', 'start_paragraph_id': 3, 'end_paragraph_id': 3, 'meta': {'evidence_span': ['The Stolichna Municipality (, "Stolichna obshtina" (also transcribed as "Stolična obština"), "Capital Municipality") is an obshtina ("municipality") in Sofia City Province, Western Bulgaria.', 'The Stolichna Municipality (, "Stolichna obshtina" (also transcribed as "Stolična obština"), "Capital Municipality") is an obshtina ("municipality") in Sofia City Province, Western Bulgaria']}}]}]