Question: calcutta was capital of british till which year
[{'answer': '1911', 'provenance': [{'wikipedia_id': '1774390', 'title': 'History of Kolkata', 'start_paragraph_id': 1, 'start_character': 333, 'end_paragraph_id': 1, 'end_character': 337, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '1774390', 'title': 'History of Kolkata', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 583, 'bleu_score': 0.9649773185979721, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1814856957524105856}, 'section': 'Section::::Abstract.'}]}]