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': 'Downey cell is seen in - \nSelect and explain. \nA. Myeloma, B. Chronic myeloid leukemia, C. Hairy cell leukemia, D. Infectious mononucleosis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]