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: Medicine
[{'content': 'Which of the following has the worst prognosis \nSelect and explain. \nA. Cholecystectomy, B. Splencetomy, C. Nephrectomy, D. Appendicetomy', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]