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': 'Commonest manifestation of endometriosis is : \nSelect and explain. \nA. Infeility, B. Pain, C. Bleeding, D. Leukorrhoea', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Pain', 'role': 'assistant'}]