Question: when did british columbia became part of canada
[{'answer': 'July 20 , 1871', 'provenance': [{'wikipedia_id': '509891', 'title': 'History of British Columbia', 'start_paragraph_id': 66, 'start_character': 512, 'end_paragraph_id': 66, 'end_character': 526, 'bleu_score': 1.0, 'section': 'Section::::Entry into Canada (1871–1900).\n'}]}, {'provenance': [{'wikipedia_id': '509891', 'title': 'History of British Columbia', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 558, 'bleu_score': 0.976327165973018, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16456940132427201578}, 'section': 'Section::::Abstract.'}]}]