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': 'Heat stable alkaline phosphatase In pregnancy is derived from : \nSelect and explain. \nA. Placenta, B. Maternal liver, C. Fetal liver, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Placenta', 'role': 'assistant'}]