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: Surgery
[{'content': 'Splenectomy is least useful in \nSelect and explain. \nA. Congenital elliptocytosis, B. Thalasemia major, C. Congenital spherocytic anaemia, D. Hereditary nonspherocytic haemolytic anaemia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]