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: Gynaecology & Obstetrics
[{'content': 'Low MSAFP is seen in all except : \nSelect and explain. \nA. Neural tube defect, B. Trisomy 21, C. Skeletal deformity, D. Cardiac anomaly', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Neural tube defect', 'role': 'assistant'}]