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': 'Capillary invasion of corpus luteum begins \nSelect and explain. \nA. One day after ovulation, B. 2 days after ovulation, C. 3 days after ovulation, D. 4 days after ovulation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Capillary invasion begins 2 days after ovulaton and reaches center of corpus luteum by 4th day.', 'role': 'assistant'}]