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
80 year old, asymptomatic man present with a Total leucocyte count of 1 lakh, with 80% lymphocytes and 20% FMC's. What is the most probable diagnosis - 
Select and explain. 
A. HIV, B. CML, C. CLL, D. TB
C: CLL
Answer: C: CLL 
Explanation: None