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': 'All are true about spasmodic dysmenorrhea EXCEPT : \nSelect and explain. \nA. Present just before menstruation, B. Present after 3rd day of menstrual period, C. The pain may persist for 12 - 24 hours, D. Dyspareunia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Present after 3rd day of menstrual period', 'role': 'assistant'}]