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 of the following is most acceptable theory explaining development of endometriosis \nSelect and explain. \nA. Coelomic metaplasia, B. Retrograde menstruation, C. Lymphatic spread, D. Mullerian remnants outside uterus', 'role': 'user'}, {'content': "Answer: B \nExplanation: Sampson's Theory of Retrograde menstruation is the most favoured theory explaining endometriosis.", 'role': 'assistant'}]