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 foetal blood is separated from syncytiotrophoblast with all except: \nSelect and explain. \nA. Fetal blood capillary membrane, B. Mesenchyme of intervillous blood space, C. Cytotrophoblast, D. Decidua parietalis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The maternal blood in the lacuna is never in direct contact with fetal blood. They are separated by:\n\nSyncytiotrophoblast\nCytotrophoblast\nBasement membrane\nMesoderm\nEndothelium of fetal capillaries\n\nTogether called as placental barrier or membrane (0.025 mm)', 'role': 'assistant'}]