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: Anatomy
[{'content': 'Embryo implanted in uterus by ? \nSelect and explain. \nA. 14 days, B. 28 days, C. 8 weeks, D. 24 weeks', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]