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': 'Which is true of endometriosis : \nSelect and explain. \nA. Always associated with tubal blood, B. Painful, C. Amenorrhoea, D. Surgery Is curative', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Painful', 'role': 'assistant'}]