This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Placenta - Types and their complications, Subject name: Gynaecology & Obstetrics
[{'content': 'At what POG placental and fetal weights are approximately equal \nSelect and explain. \nA. 15 week, B. 17 week, C. 19 week, D. 21 week', 'role': 'user'}, {'content': 'Answer: B \nExplanation: By approximately 17 postmenstrual weeks,placental and fetal weights are approximately equal. By term, placental weight is approximately one sixth of fetal weight.', 'role': 'assistant'}]