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': 'In - vitro feilisation is indicated in : \nSelect and explain. \nA. Anovulatory cycles, B. Tubal block, C. Azoospermia, D. Uterine anomalies', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Tubal block', 'role': 'assistant'}]