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': "80 year old, asymptomatic man present with a Total Leucocyte Count of 100,000, with 80% lymphocytes and 20% PMC's. What is the most probable diagnosis? \nSelect and explain. \nA. HIV, B. CML, C. CLL, D. TB", 'role': 'user'}, {'content': "Answer: C \nExplanation: An elderly asymptomatic patient presenting with an incidental finding of absolute lymphocytosis suggests the possible diagnosis of Chronic Lymphoid Leukemia (CLL). Ref: Harrison's Principles of Internal Medicine, 17th Edition, Page 693; 16th Edition, Page 648; Davidson's Principles and Practice of Medicine, 20th Edition, Page 1046", 'role': 'assistant'}]