This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
[{'content': 'Amniotic fluid alpha fetoprotein is raised by - \nSelect and explain. \nA. Traumatic amniocentesis, B. Open neural tube defect, C. Intra uterine fetal death, D. None', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans-B', 'role': 'assistant'}]