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': 'Which one of the following biochemical parameters is the most sensitive to detect open spina bifida ? \nSelect and explain. \nA. Maternal serum alpha fetoprotein, B. Amniotic fluid alpha fetoprotein, C. Amniotic fluid acetyl cholinesterase, D. Amniotic fluid glucohexaminase', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]