This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2018, Subject name: Gynaecology & Obstetrics
[{'content': "EDD ( Expected Date of Delivery) is calculated by: \nSelect and explain. \nA. Young's rule, B. Naegele's formula, C. Cardiff Formula, D. Hadlock Formula", 'role': 'user'}, {'content': "Answer: B \nExplanation: Expected date of delivery is calculated by - Naegele's formula From the 1st day of last menstrual cycle - 9 months + 7 days", 'role': 'assistant'}]