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 formation of primordial follicles in human fetus is completed by : \nSelect and explain. \nA. 4 weeks, B. 8 weeks, C. 13 weeks, D. 18 weeks', 'role': 'user'}, {'content': 'Answer: D \nExplanation: 18 weeks', 'role': 'assistant'}]