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': 'Very often the first indication a woman has that she is pregnant is a missed menstrual period. In which week of embryonic development will a woman experience her first missed menstrual period? \nSelect and explain. \nA. Sta of week 3, B. Sta of week 4, C. Sta of week 5, D. Sta of week 6', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Feilization of ovum takes place on day-15 of menstrual cycle. woman notices missing of next menstrual period from day1- day5 if implantation takes place. That day corresponds to sta of 3rd week of embryonic development ( day15-day28-day1-5 of next cycle= >14 days)', 'role': 'assistant'}]