Question: when did nigeria became a colony of britain
[{'answer': '1914', 'provenance': [{'wikipedia_id': '9329483', 'title': 'Colonial Nigeria', 'start_paragraph_id': 4, 'start_character': 393, 'end_paragraph_id': 4, 'end_character': 397, 'bleu_score': 1.0, 'section': 'Section::::Overview.\n'}]}, {'provenance': [{'wikipedia_id': '9329483', 'title': 'Colonial Nigeria', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 627, 'bleu_score': 0.955468993395951, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15674707160515723911}, 'section': 'Section::::Overview.\n'}]}]