Question: what is the name of the first president of nigeria
[{'answer': 'Muhammadu Buhari', 'provenance': [{'wikipedia_id': '516088', 'title': 'President of Nigeria', 'start_paragraph_id': 1, 'start_character': 506, 'end_paragraph_id': 1, 'end_character': 522, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '516088', 'title': 'President of Nigeria', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 537, 'bleu_score': 0.7796467268290991, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10008582847565672276}, 'section': 'Section::::Abstract.'}]}]