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': 'The fetal blood is separated from maternal blood with all except : \nSelect and explain. \nA. Extra embryonic mesoderm, B. Syncytio trophoblast, C. Cyto trophoblast, D. Decidua parietalis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Decidua parietalis', 'role': 'assistant'}]