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: Pathology
[{'content': 'Conditions predisposing to leukemia include all except - \nSelect and explain. \nA. Ionising radiation, B. Myelofibrosis, C. Infectious mononucleosis, D. Polycythemia vera', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]