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': 'In pregnancy, calculation of EDD (expected date of delivery) considers: March 2013 \nSelect and explain. \nA. First day of last menstruation, B. Last day of last menstruation period, C. Mid time of last menstrual period, D. Day of coitus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A i.e. First day of last menstruation', 'role': 'assistant'}]