This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Development period- week 1,2,3,4, Subject name: Anatomy
[{'content': 'The indifferent embryo begins phenotypic sexual differentiation during \nSelect and explain. \nA. Week 3 of development, B. Week 5 of development, C. Week 7 of development, D. Week 12 of development', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The embryo during weeks 1-6 remains in an undifferentiated stage. The embryo begins phenotypic sexual differentiation during week 7.', 'role': 'assistant'}]