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: Radiology
[{'content': 'Egg-shell calcification in hilar lymph nodes is seen in : \nSelect and explain. \nA. Sarcoidosis, B. Histoplasmosis, C. Tuberculosis, D. Carcinoma lung', 'role': 'user'}, {'content': "Answer: B \nExplanation: B i.e. Waterston Cooley's shunt", 'role': 'assistant'}]