This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Anatomy
[{'content': 'Percentage of women who deliver on expected date of delivery \nSelect and explain. \nA. 4%, B. 15%, C. 35%, D. 70%', 'role': 'user'}, {'content': "Answer: A \nExplanation: EDD is calculated using Naegle's rule", 'role': 'assistant'}]