Question: when did bihar bifurcate from bengal and some parts of chota nagpur merged into bengal
[{'answer': '1912', 'provenance': [{'wikipedia_id': '4332811', 'title': 'Chota Nagpur Division', 'start_paragraph_id': 5, 'start_character': 97, 'end_paragraph_id': 5, 'end_character': 101, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '4332811', 'title': 'Chota Nagpur Division', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10024574680748318397}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '4332811', 'title': 'Chota Nagpur Division', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 267, 'bleu_score': 0.957870874785216, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10024574680748318397}, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '4332811', 'title': 'Chota Nagpur Division', 'section': 'Section::::History.\n', 'start_paragraph_id': 5, 'end_paragraph_id': 5, 'meta': {'evidence_span': ['Chota Nagpur Division became part of the new province of Bihar and Orissa when it was created in 1912', 'Chota Nagpur Division became part of the new province of Bihar and Orissa when it was created in 1912.', 'Chota Nagpur Division became part of the new province of Bihar and Orissa when it was created in 1912']}}]}, {'provenance': [{'wikipedia_id': '43313311', 'title': 'Assam Province', 'section': 'Section::::History.\n', 'start_paragraph_id': 9, 'end_paragraph_id': 9, 'meta': {'evidence_span': ['he province was annulled in 1911 following a sustained mass protest campaign and on 1 April 1912 the two parts of Bengal were reunited and a new partition based on language followed, Oriya and Assamese areas were separated to form new administrative units: Bihar and Orissa Province was created to the west, and Assam Province to the east.', 'on 1 April 1912 the two parts of Bengal were reunited and a new partition based on language followed']}}]}]